词条 | Fertility |
释义 |
Fertility is the natural capability to produce offspring. As a measure, fertility rate is the number of offspring born per mating pair, individual or population. Fertility differs from fecundity, which is defined as the potential for reproduction (influenced by gamete production, fertilization and carrying a pregnancy to term) {{Citation needed | reason=Definition is disputed among demographers and biologists, demographers and biologists have opposite definitions of fecundity and fertility; refer Fecundity page|date=July 2013}}. A lack of fertility is infertility while a lack of fecundity would be called sterility. Human fertility depends on factors of nutrition, sexual behavior, consanguinity, culture, instinct, endocrinology, timing, economics, way of life, and emotions. DemographyIn demographic contexts, fertility refers to the actual production of offspring, rather than the physical capability to produce which is termed fecundity.[1][2] While fertility can be measured, fecundity cannot be. Demographers measure the fertility rate in a variety of ways, which can be broadly broken into "period" measures and "cohort" measures. "Period" measures refer to a cross-section of the population in one year. "Cohort" data on the other hand, follows the same people over a period of decades. Both period and cohort measures are widely used.[3] Period measures
Cohort measures
Social and economic determinants of fertility{{Main article|fertility factor (demography)}}A parent's number of children strongly correlates with the number of children that each person in the next generation will eventually have.[5] Factors generally associated with increased fertility include religiosity,[6] intention to have children,[7] and maternal support.[8] Factors generally associated with decreased fertility include wealth, education,[9] female labor participation,[10] urban residence,[11] intelligence, increased female age and (to a lesser degree) increased male age. The "Three-step Analysis" of the fertility process was introduced by Kingsley Davis and Judith Blake in 1956 and makes use of three proximate determinants:[12][13] The economic analysis of fertility is part of household economics, a field that has grown out of the New Home Economics. Influential economic analyses of fertility include Becker (1960),[14] Mincer (1963),[15] and Easterlin (1969).[16] The latter developed the Easterlin hypothesis to account for the Baby Boom. Bongaarts' model of components of fertilityBongaarts proposed a model where the total fertility rate of a population can be calculated from four proximate determinants and the total fecundity (TF). The index of marriage (Cm), the index of contraception (Cc), the index of induced abortion (Ca) and the index of postpartum infecundability (Ci). These indices range from 0 to 1. The higher the index, the higher it will make the TFR, for example a population where there are no induced abortions would have a Ca of 1, but a country where everybody used infallible contraception would have a Cc of 0. TFR = TF × Cm × Ci × Ca × Cc These four indices can also be used to calculate the total marital fertility (TMFR) and the total natural fertility (TN). TFR = TMFR × Cm TMFR = TN × Cc × Ca TN = TF × Ci
The first step is sexual intercourse, and an examination of the average age at first intercourse, the average frequency outside marriage, and the average frequency inside.
Certain physical conditions may make it impossible for a woman to conceive. This is called "involuntary infecundity." If the woman has a condition making it possible, but unlikely to conceive, this is termed "subfecundity." Venereal diseases (especially gonorrhea, syphilis, and chlamydia) are common causes. Nutrition is a factor as well: women with less than 20% body fat may be subfecund, a factor of concern for athletes and people susceptible to anorexia. Demographer Ruth Frisch has argued that "It takes 50,000 calories to make a baby". There is also subfecundity in the weeks following childbirth, and this can be prolonged for a year or more through breastfeeding. A furious political debate raged in the 1980s over the ethics of baby food companies marketing infant formula in developing countries. A large industry has developed to deal with subfecundity in women and men. An equally large industry has emerged to provide contraceptive devices designed to prevent conception. Their effectiveness in use varies. On average, 85% of married couples using no contraception will have a pregnancy in one year. The rate drops to the 20% range when using withdrawal, vaginal sponges, or spermicides. (This assumes the partners never forget to use the contraceptive.) The rate drops to only 2 or 3% when using the pill or an IUD, and drops to near 0% for implants and 0% for tubal ligation (sterilization) of the woman, or a vasectomy for the man.
After a fetus is conceived, it may or may not survive to birth. "Involuntary fetal mortality" involves natural abortion, miscarriages and stillbirth (a fetus born dead). Human intervention intentionally causing abortion of the fetus is called "therapeutic abortion". Fertility biologyWomen have hormonal cycles which determine when they can achieve pregnancy. The cycle is approximately twenty-eight days long, with a fertile period of five days per cycle, but can deviate greatly from this norm. Men are fertile continuously, but their sperm quality is affected by their health, frequency of ejaculation, and environmental factors. Fertility declines with age in both sexes. In women the decline is more rapid, with complete infertility normally occurring around the age of 50. Pregnancy rates for sexual intercourse are highest when it is done every 1 or 2 days,[17] or every 2 or 3 days.[18] Studies have shown no significant difference between different sex positions and pregnancy rate, as long as it results in ejaculation into the vagina.[19]Menstrual cycle{{Main article|Menstrual cycle}}A woman's menstrual cycle begins, as it has been arbitrarily assigned, with menses. Next is the follicular phase where estrogen levels build as an ovum matures (due to the follicular stimulating hormone, or FSH) within the ovary. When estrogen levels peak, it spurs a surge of luteinizing hormone (LH) which finishes the ovum and enables it to break through the ovary wall. This is ovulation. During the luteal phase, which follows ovulation LH and FSH cause the post-ovulation ovary to develop into the corpus luteum which produces progesterone. The production of progesterone inhibits the LH and FSH hormones which (in a cycle without pregnancy) causes the corpus luteum to atrophy, and menses to begin the cycle again. Peak fertility occurs during just a few days of the cycle: usually two days before and two days after the ovulation date.[21] This fertile window varies from woman to woman, just as the ovulation date often varies from cycle to cycle for the same woman.[22] The ovule is usually capable of being fertilized for up to 48 hours after it is released from the ovary. Sperm survive inside the uterus between 48 and 72 hours on average, with the maximum being 120 hours (5 days). These periods and intervals are important factors for couples using the rhythm method of contraception. Female fertility{{Further information|Female infertility}}The average age of menarche in the United States is about 12.5 years.[23] In postmenarchal girls, about 80% of the cycles are anovulatory (ovulation does not actually take place) in the first year after menarche, 50% in the third and 10% in the sixth year.[24][25] Menopause occurs during a woman's midlife (between ages 48 and 55).[26][27] During menopause, hormonal production by the ovaries is reduced, eventually causing a permanent cessation of the primary function of the ovaries, particularly the creation of the uterine lining (period). This is considered the end of the fertile phase of a woman's life. The following effects of age and female fertility have been found in women trying to get pregnant, without using fertility drugs or in vitro fertilization:[28]
Studies of actual couples trying to conceive have come up with higher results: one 2004 study of 770 European women found that 82% of 35- to 39-year-old women conceived within a year,[29] while another in 2013 of 2,820 Danish women saw 78% of 35- to 40-year-olds conceive within a year.[30] The use of fertility drugs and/or invitro fertilization can increase the chances of becoming pregnant at a later age.[31] Successful pregnancies facilitated by fertility treatment have been documented in women as old as 67.[32] Studies since 2004 now show that mammals may continue to produce new eggs throughout their lives, rather than being born with a finite number as previously thought. Researchers at the Massachusetts General Hospital in Boston, US, say that if eggs are newly created each month in humans as well, all current theories about the aging of the female reproductive system will have to be overhauled, although at this time this is simply conjecture.[33][34] According to the March of Dimes, "about 9 percent of recognized pregnancies for women aged 20 to 24 ended in miscarriage. The risk rose to about 20 percent at age 35 to 39, and more than 50 percent by age 42".[35] Birth defects, especially those involving chromosome number and arrangement, also increase with the age of the mother. According to the March of Dimes, "At age 25, your risk of having a baby with Down syndrome is 1 in 1,340. At age 30, your risk is 1 in 940. At age 35, your risk is 1 in 353. At age 40, your risk is 1 in 85. At age 45, your risk is 1 in 35."[36] Male fertility{{see also|Paternal age effect|Male infertility}}Some research suggest that increased male age is associated with a decline in semen volume, sperm motility, and sperm morphology.[37] In studies that controlled for female age, comparisons between men under 30 and men over 50 found relative decreases in pregnancy rates between 23% and 38%.[37] It is suggested that sperm count declines with age, with men aged 50–80 years producing sperm at an average rate of 75% compared with men aged 20–50 years and that larger differences are seen in how many of the seminiferous tubules in the testes contain mature sperm:[37]
Decline in male fertility is influenced by many factors, including lifestyle, environment and psychological factors.[39] Some research also suggests increased risks for health problems for children of older fathers, but no clear association has been proven.[40] A large scale in Israel study suggested that the children of men 40 or older were 5.75 times more likely than children of men under 30 to have an autism spectrum disorder, controlling for year of birth, socioeconomic status, and maternal age.[41] Increased paternal age is suggested by some to directly correlate to schizophrenia but it is not proven.[42][43][44][45][46] Australian researchers have found evidence to suggest overweight obesity may cause subtle damage to sperm and prevent a healthy pregnancy. They say fertilization was 40% less likely to succeed when the father was overweight.[47] The American Fertility Society recommends an age limit for sperm donors of 50 years or less,[48] and many fertility clinics in the United Kingdom will not accept donations from men over 40 or 45 years of age.[49] Historical trends by country{{Main article|Historical demography}}{{See also|Demographic transition}}France{{main article|Demographics of France}}The French pronatalist movement from 1919–1945 failed to convince French couples they had a patriotic duty to help increase their country's birthrate. Even the government was reluctant in its support to the movement. It was only between 1938 and 1939 that the French government became directly and permanently involved in the pronatalist effort. Although the birthrate started to surge in late 1941, the trend was not sustained. Falling birthrate once again became a major concern among demographers and government officials beginning in the 1970s.[50] United States{{main article|Demographic history of the United States}}From 1800 to 1940, fertility fell in the US. There was a marked decline in fertility in the early 1900s, associated with improved contraceptives, greater access to contraceptives and sexuality information and the "first" sexual revolution in the 1920s. Post-WWII{{Main article|Baby Boom}}After 1940 fertility suddenly started going up again, reaching a new peak in 1957. After 1960, fertility started declining rapidly. In the Baby Boom years (1946–1964), women married earlier and had their babies sooner; the number of children born to mothers after age 35 did not increase. Sexual revolution{{see also|Sexual revolution in 1960s America}}After 1960, new methods of contraception became available, ideal family size fell, from 3 to 2 children. Couples postponed marriage and first births, and they sharply reduced the number of third and fourth births.{{citation needed|date=August 2015}} Infertility{{Main article|Infertility}}Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term. There are many biological causes of infertility, including some that medical intervention can treat.[52]See also{{Div col|colwidth=20em}}
Footnotes1. ^{{cite web|url=http://www.gfmer.ch/Books/Reproductive_health/The_demography_of_fertility_and_infertility.html|title=The demography of fertility and infertility|website=www.gfmer.ch}} 2. ^http://www.enotes.com/public-health-encyclopedia/fecundity-fertility 3. ^For detailed discussions of each measure see Paul George Demeny and Geoffrey McNicoll, Encyclopedia of Population (2003) 4. ^Another way of doing it is to add up the ASFR for age 10-14, 15-19, 20-24, etc., and multiply by 5 (to cover the 5 year interval). 5. ^{{cite journal|last1=Murphy|first1=Michael|title=Cross-National Patterns of Intergenerational Continuities in Childbearing in Developed Countries|journal=Biodemography and Social Biology|volume=59|issue=2|year=2013|pages=101–126|issn=1948-5565|doi=10.1080/19485565.2013.833779|pmid=24215254|pmc=4160295}} 6. ^{{Cite journal | doi = 10.1353/sof.0.0000| pmid = 19672317| title = Religiosity and Fertility in the United States: The Role of Fertility Intentions| journal = Social Forces| volume = 86| issue = 3| pages = 1163–1188| year = 2008| last1 = Hayford | first1 = S. R.| last2 = Morgan | first2 = S. P.| pmc = 2723861}} 7. ^{{cite web|url=http://www.ssb.no/en/forskning/discussion-papers/_attachment/182990?_ts=146a3818d38|author1=Lars Dommermuth |author2=Jane Klobas |author3=Trude Lappegård |title=Differences in childbearing by time frame of fertility intention. A study using survey and register data from Norway|year=2014}} Part of the research project Family Dynamics, Fertility Choices and Family Policy (FAMDYN) 8. ^{{cite journal|last1=Schaffnit|first1=S. B.|last2=Sear|first2=R.|title=Wealth modifies relationships between kin and women's fertility in high-income countries|journal=Behavioral Ecology|volume=25|issue=4|year=2014|pages=834–842|issn=1045-2249|doi=10.1093/beheco/aru059}} 9. ^{{cite journal|title=Regression Analysis of Collinear Data using r-k Class Estimator: Socio-Economic and Demographic Factors Affecting the Total Fertility Rate (TFR) in India.|journal=Journal of Data Science|year=2013|volume=11|last1=Rai|first1=Piyush Kant|last2=Pareek|first2=Sarla|last3=Joshi|first3=Hemlata|url=http://www.jds-online.com/file_download/394/JDS-1130.pdf}} 10. ^{{cite journal |first=David |last=Bloom |first2=David |last2=Canning |first3=Günther |last3=Fink |first4=Jocelyn |last4=Finlay |year=2009 |title=Fertility, female labor force participation, and the demographic dividend |journal=Journal of Economic Growth |volume=14 |issue=2 |pages=79–101 |doi=10.1007/s10887-009-9039-9 }} 11. ^{{citation|url=http://ir.nul.nagoya-u.ac.jp/jspui/bitstream/2237/8650/1/ysatoJUE.pdf|title=Economic geography, fertility and migration|first=Yasuhiro|last=Sato|journal=Journal of Urban Economics|date=30 July 2006|accessdate=31 March 2008}} 12. ^{{cite journal | last1 = Bongaarts | first1 = John | author-link1 = John Bongaarts | year = 1978 | title = A Framework for Analyzing the Proximate Determinants of Fertility | journal = Population and Development Review | volume = 4 | issue = 1| pages = 105–132 | jstor=1972149 | doi=10.2307/1972149}} 13. ^{{cite journal | last1 = Stover | first1 = John | year = 1998 | title = Revising the Proximate Determinants of Fertility Framework: What Have We Learned in the past 20 Years? | journal = Studies in Family Planning | volume = 29 | issue = 3| pages = 255–267 | jstor=172272 | doi=10.2307/172272}} 14. ^Becker, Gary S. 1960. "An Economic Analysis of Fertility." In National Bureau Committee for Economic Research, Demographic and Economic Change in Developed Countries, a Conference of the Universities. Princeton, N.J.: Princeton University Press 15. ^Mincer, Jacob. 1963. "Market Prices, Opportunity Costs, and Income Effects," in C. Christ (ed.) Measurement in Economics. Stanford, CA: Stanford University Press 16. ^{{cite journal | last1 = Easterlin | first1 = Richard A. | year = 1975 | title = An Economic Framework for Fertility Analysis| url = | journal = Studies in Family Planning | volume = 6 | issue = 3| pages = 54–63 | doi=10.2307/1964934| pmid = 1118873 | jstor = 1964934 }} 17. ^{{cite web|url=https://www.mayoclinic.org/healthy-lifestyle/getting-pregnant/in-depth/how-to-get-pregnant/art-20047611|title=How to get pregnant|website=Mayo Clinic|date=2016-11-02|accessdate=2018-02-16}} 18. ^{{cite web|url=https://www.nice.org.uk/guidance/cg156/ifp/chapter/trying-for-a-baby|title=Fertility problems: assessment and treatment, Clinical guideline [CG156]|website=National Institute for Health and Care Excellence|accessdate=2018-02-16}} Published date: February 2013. Last updated: September 2017 19. ^{{cite web|url=http://americanpregnancy.org/getting-pregnant-ebook/p7M7O0q1c71703C/gettingpregnant.pdf|title=The Essential Guide to Getting Pregnant|website=American Pregnancy Association|author=Dr. Philip B. Imler & David Wilbanks}} 20. ^{{cite journal|last1=Dunson|first1=D.B.|last2=Baird|first2=D.D.|last3=Wilcox|first3=A.J.|last4=Weinberg|first4=C.R.|title=Day-specific probabilities of clinical pregnancy based on two studies with imperfect measures of ovulation|journal=Human Reproduction|volume=14|issue=7|year=1999|pages=1835–1839|issn=1460-2350|doi=10.1093/humrep/14.7.1835}} 21. ^{{cite web |url=http://www.duofertility.com/en/my-body/my-cycle/my-fertile-period.html |title=Archived copy |accessdate=2008-09-22 |deadurl=yes |archiveurl=https://web.archive.org/web/20081221225600/http://www.duofertility.com/en/my-body/my-cycle/my-fertile-period.html |archivedate=2008-12-21 |df= }} 22. ^{{cite journal |last1=Creinin |first1=Mitchell D. |last2=Keverline |first2=Sharon |last3=Meyn |first3=Leslie A. |title=How regular is regular? An analysis of menstrual cycle regularity |journal=Contraception |volume=70 |issue=4 |pages=289–92 |year=2004 |pmid=15451332 |doi=10.1016/j.contraception.2004.04.012 }} 23. ^{{cite journal |last1=Anderson |first1=S. E. |last2=Dallal |first2=G. E. |last3=Must |first3=A. |title=Relative Weight and Race Influence Average Age at Menarche: Results From Two Nationally Representative Surveys of US Girls Studied 25 Years Apart |journal=Pediatrics |volume=111 |issue=4 Pt 1 |pages=844–50 |year=2003 |pmid=12671122 |doi=10.1542/peds.111.4.844 }} 24. ^{{cite journal |author=Apter D |title=Serum steroids and pituitary hormones in female puberty: a partly longitudinal study |journal=Clin. Endocrinol. |volume=12 |issue=2 |pages=107–20 |date=February 1980 |pmid=6249519 |doi= 10.1111/j.1365-2265.1980.tb02125.x|url=}} 25. ^{{cite journal |last1=Apter |first1=D |title=Serum steroids and pituitary hormones in female puberty: a partly longitudinal study |journal=Clinical Endocrinology |volume=12 |issue=2 |pages=107–20 |year=1980 |pmid=6249519 |doi=10.1111/j.1365-2265.1980.tb02125.x }} 26. ^{{cite journal|last1=Takahashi|first1=TA|last2=Johnson|first2=KM|title=Menopause.|journal=The Medical Clinics of North America|date=May 2015|volume=99|issue=3|pages=521–34|pmid=25841598|doi=10.1016/j.mcna.2015.01.006}} 27. ^{{cite book|url=https://books.google.com/?id=SozvHsW4VysC&pg=PA435&dq=gynecology%20menopause%20range%2048-55#v=onepage&q&f=false|title=Obstetrics and Gynecology Recall|first1=F. John|last1=Bourgeois|first2=Paola A.|last2=Gehrig|first3=Daniel S.|last3=Veljovich|date=1 January 2005|publisher=Lippincott Williams & Wilkins|via=Google Books|isbn=9780781748797}} 28. ^1 A computer simulation run by Henri Leridon, PhD, an epidemiologist with the French Institute of Health and Medical Research*{{cite journal |last1=Leridon |first1=H. |title=Can assisted reproduction technology compensate for the natural decline in fertility with age? A model assessment |journal=Human Reproduction |volume=19 |issue=7 |pages=1548–53 |year=2004 |pmid=15205397 |doi=10.1093/humrep/deh304}} 29. ^{{cite journal |last1=Dunson |first1=David B. |last2=Baird |first2=Donna D. |last3=Colombo |first3=Bernardo |title=Increased Infertility With Age in Men and Women |journal=Obstetrics & Gynecology |volume=103 |issue=1 |pages=51–6 |year=2004 |pmid=14704244 |doi=10.1097/01.AOG.0000100153.24061.45 }} 30. ^{{cite journal |last1=Rothman |first1=Kenneth J. |last2=Wise |first2=Lauren A. |last3=Sørensen |first3=Henrik T. |last4=Riis |first4=Anders H. |last5=Mikkelsen |first5=Ellen M. |last6=Hatch |first6=Elizabeth E. |title=Volitional determinants and age-related decline in fecundability: a general population prospective cohort study in Denmark |journal=Fertility and Sterility |volume=99 |issue=7 |pages=1958–64 |year=2013 |pmid=23517858 |pmc=3672329 |doi=10.1016/j.fertnstert.2013.02.040 }} 31. ^Fertility Nutraceuticals, LLC "How to improve IVF success rates with smart fertility supplement strategy' May 6, 2014{{MEDRS|date=August 2015}} 32. ^{{cite news|title=Spanish woman ' is oldest mother' | date=2006-12-30|accessdate=2006-12-30|url=http://news.bbc.co.uk/2/hi/health/6220523.stm|publisher=BBC News}} 33. ^{{cite journal |last1=Couzin |first1=Jennifer |title=Reproductive Biology: Textbook Rewrite? Adult Mammals May Produce Eggs After All |journal=Science |volume=303 |issue=5664 |pages=1593 |year=2004 |pmid=15016968 |doi=10.1126/science.303.5664.1593a }} 34. ^{{cite journal | year = 2010| title = Human Ovarian Reserve from Conception to the Menopause | url = | journal = PLoS ONE | volume = 5 | issue = 1| page = e8772 | doi = 10.1371/journal.pone.0008772 | pmid=20111701 | pmc=2811725 | last1 = Wallace | first1 = WH | last2 = Kelsey | first2 = TW | bibcode = 2010PLoSO...5.8772W | arxiv = 1106.1382 }} 35. ^{{cite web | title=Pregnancy After 35 | work=March of Dimes | url=http://www.marchofdimes.org/pregnancy/a-mommy-after-35.aspx | accessdate=October 30, 2014}} 36. ^{{cite web|url=http://www.marchofdimes.org/baby/down-syndrome.aspx|title=Down syndrome|publisher=}} 37. ^1 2 {{cite journal |last1=Kidd |first1=Sharon A |last2=Eskenazi |first2=Brenda |last3=Wyrobek |first3=Andrew J |title=Effects of male age on semen quality and fertility: a review of the literature |journal=Fertility and Sterility |volume=75 |issue=2 |pages=237–48 |year=2001 |pmid=11172821 |doi=10.1016/S0015-0282(00)01679-4 }} 38. ^Effect of Age on Male Fertility Seminars in Reproductive Endocrinology. Volume, Number 3, August 1991. Sherman J. Silber, M.D. 39. ^{{cite journal |last1=Campagne |first1=Daniel M. |title=Can Male Fertility Be Improved Prior to Assisted Reproduction through The Control of Uncommonly Considered Factors? |journal=International Journal of Fertility & Sterility |volume=6 |issue=4 |pages=214–23 |year=2013 |pmid=24520443 |pmc=3850314 }} 40. ^{{cite journal|title=Advanced paternal age and reproductive outcome|first1=Zofnat|last1=Wiener-Megnazi|first2=Ron|last2=Auslender|first3=Martha|last3=Dirnfeld|date=1 January 2012|publisher=|journal=Asian J Androl|volume=14|issue=1|pages=69–76|doi=10.1038/aja.2011.69|pmid=22157982|pmc=3735149}} 41. ^{{cite journal |last1=Reichenberg |first1=Abraham |last2=Gross |first2=Raz |last3=Weiser |first3=Mark |last4=Bresnahan |first4=Michealine |last5=Silverman |first5=Jeremy |last6=Harlap |first6=Susan |last7=Rabinowitz |first7=Jonathan |last8=Shulman |first8=Cory |last9=Malaspina |first9=Dolores |last10=Lubin |first10=Gad |last11=Knobler |first11=Haim Y. |last12=Davidson |first12=Michael |last13=Susser |first13=Ezra |title=Advancing Paternal Age and Autism |journal=Archives of General Psychiatry |volume=63 |issue=9 |pages=1026–32 |year=2006 |pmid=16953005 |doi=10.1001/archpsyc.63.9.1026 }} 42. ^{{cite journal|title=Paternal age, de novo mutations and schizophrenia|first1=AE|last1=Jaffe|first2=WW|last2=Eaton|first3=RE|last3=Straub|first4=S|last4=Marenco|first5=DR|last5=Weinberger|date=1 March 2014|publisher=|journal=Mol Psychiatry|volume=19|issue=3|pages=274–275|doi=10.1038/mp.2013.76|pmid=23752248|pmc=3929531}} 43. ^{{cite book|url=https://books.google.com/?id=guomDAAAQBAJ&pg=PA47&lpg=PA47&dq=Increased%20father%20age%20not%20proven%20to%20schizophrenia%20however%20findings%20do%20not%20%20consistently%20support#v=onepage&q&f=false|title=Schizophrenia and Psychotic Spectrum Disorders|first1=S. Charles|last1=Schulz|first2=Michael F.|last2=Green|first3=Katharine J.|last3=Nelson|date=1 April 2016|publisher=Oxford University Press|via=Google Books|isbn=9780199378074}} 44. ^{{cite journal |last1=Malaspina |first1=Dolores |last2=Harlap |first2=Susan |last3=Fennig |first3=Shmuel |last4=Heiman |first4=Dov |last5=Nahon |first5=Daniella |last6=Feldman |first6=Dina |last7=Susser |first7=Ezra S. |title=Advancing Paternal Age and the Risk of Schizophrenia |journal=Archives of General Psychiatry |volume=58 |issue=4 |pages=361–7 |year=2001 |pmid=11296097 |doi=10.1001/archpsyc.58.4.361 }} 45. ^{{cite journal |last1=Sipos |first1=Attila|last2=Rasmussen |first2=Finn |last3=Harrison |first3=Glynn |last4=Tynelius |first4=Per |last5=Lewis |first5=Glyn |last6=Leon |first6=David A |last7=Gunnell |first7=David |title=Paternal age and schizophrenia: a population based cohort study |journal=BMJ |volume=329 |issue=7474 |pages=1070 |year=2004 |pmid=15501901 |pmc=526116 |doi=10.1136/bmj.38243.672396.55 }} 46. ^{{cite journal |last1=Malaspina |first1=Dolores |last2=Corcoran |first2=Cheryl |last3=Fahim |first3=Cherine |last4=Berman |first4=Ariela |last5=Harkavy-Friedman |first5=Jill |last6=Yale |first6=Scott |last7=Goetz |first7=Deborah |last8=Goetz |first8=Raymond |last9=Harlap |first9=Susan |last10=Gorman |first10=Jack |title=Paternal age and sporadic schizophrenia: Evidence for de novo mutations |journal=American Journal of Medical Genetics |volume=114 |issue=3 |pages=299–303 |year=2002 |pmid=11920852 |pmc=2982144 |doi=10.1002/ajmg.1701 }} 47. ^{{cite news|title=Obesity | Fat men linked to low fertility |url=http://www.smh.com.au/lifestyle/wellbeing/fat-men-linked-to-lower-fertility-20101017-16p6l.html |publisher=Sydney Morning Herald |date=18 October 2010 |accessdate=19 October 2010}} 48. ^{{cite journal |last1=Plas |first1=E |last2=Berger |first2=P |last3=Hermann |first3=M |last4=Pflüger |first4=H |title=Effects of aging on male fertility? |journal=Experimental Gerontology |volume=35 |issue=5 |pages=543–51 |year=2000 |pmid=10978677 |doi=10.1016/S0531-5565(00)00120-0 }} 49. ^Age Limit of Sperm Donors in the United Kingdom Pdf file {{webarchive |url=https://web.archive.org/web/20081003143235/http://www.spermdonorforum.com/documents/sperm_donor_clinics_uk_2007.pdf |date=October 3, 2008 }} 50. ^{{cite journal |first1=Andrés Horacio |last1=Reggiani |date=Spring 1996 |title=Procreating France: The Politics of Demography, 1919-1945 |journal=French Historical Studies |volume=19 |issue=3 |pages=725–54 |jstor=286642 |doi=10.2307/286642}} 51. ^CDC Bottom of this page https://www.cdc.gov/nchs/products/vsus.htm "Vital Statistics of the United States, 2003, Volume I, Natality", Table 1-1 "Live births, birth rates, and fertility rates, by race: United States, 1909-2003." 52. ^{{cite journal|last1=Makar |first1=Robert S. |last2=Toth |first2=Thomas L. |title=The Evaluation of Infertility |journal=American Journal of Clinical Pathology |volume=117 Suppl |issue= |pages=S95–103 |year=2002 |pmid=14569805 |doi=10.1309/w8lj-k377-dhra-cp0b }} References{{citizendium|title=Fertility (demography)}}
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1 : Fertility |
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