title: Live birth sex ratios and father's geographic origins in Jerusalem, 1964-1976.
abstract: OBJECTIVE
  To examine whether ancestry influenced sex ratios of offspring in a birth cohort before parental antenatal sex selection influenced offspring sex.
  
  
  METHODS
  We measured the sex ratio as the percent of males according to countries of birth of paternal and maternal grandfathers in 91,459 live births from 1964 to 1976 in the Jerusalem Perinatal Study. Confidence limits (CI) were computed based on an expected sex ratio of 1.05, which is 51.4% male.
  
  
  RESULTS
  Of all live births recorded, 51.4% were male. Relative to Jewish ancestry (51.4% males), significantly more males (1,761) were born to Muslim ancestry (54.5, 95% CI = 52.1-56.8, P = 0.01). Among the former, sex ratios were not significantly associated with paternal or maternal age, education, or offspring's birth order. Consistent with a preference for male offspring, the sex ratio decreased despite increasing numbers of births over the 13-year period. Sex ratios were not affected by maternal or paternal origins in North Africa or Europe. However, the offspring whose paternal grandfathers were born in Western Asia included fewer males than expected (50.7, 50.1-51.3, P = 0.02), whether the father was born abroad (50.7) or in Israel (50.8). This was observed for descendents of paternal grandfathers born in Lebanon (47.6), Turkey (49.9), Yemen & Aden (50.2), Iraq (50.5), Afghanistan (50.5), Syria (50.6), and Cyprus (50.7); but not for those from India (51.5) or Iran (51.9). The West Asian group showed the strongest decline in sex ratios with increasing paternal family size.
  
  
  CONCLUSIONS
  A decreased sex ratio associated with ancestry in Western Asia is consistent with reduced ability to bear sons by a subset of Jewish men in the Jerusalem cohort. Lower sex ratios may be because of pregnancy stress, which may be higher in this subgroup. Alternatively, a degrading Y chromosome haplogroup or other genetic or epigenetic differences on male germ lines could affect birth ratios, such as differential exposure to an environmental agent, dietary differences, or stress. Differential stopping behaviors that favor additional pregnancies following the birth of a daughter might exacerbate these lower sex ratios.
authors.affiliation: College of Medicine, SUNY Downstate, Brooklyn, New York, 11203.
authors.forename: J
authors.initials: J
authors.lastname: Groeger
authors.affiliation: Department of Psychiatry, New York University School of Medicine, 1 Park Avenue, Floor 8, New York, New York, 10016, USA.|Prophase, 3 Park Avenue, New York, New York, 10016.
authors.forename: M
authors.initials: M
authors.lastname: Opler
authors.affiliation: Department of Psychiatry, New York University School of Medicine, 1 Park Avenue, Floor 8, New York, New York, 10016, USA.
authors.forename: K
authors.initials: K
authors.lastname: Kleinhaus
authors.affiliation: Department of Psychiatry, New York University School of Medicine, 1 Park Avenue, Floor 8, New York, New York, 10016, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Perrin
authors.affiliation: Braun School of Public Health, Hebrew University-Hadassah School of Public Health, Jerusalem, 91120, Israel.|Department of Sociology, Princeton University, Princeton, New Jersey, 08544.
authors.forename: R
authors.initials: R
authors.lastname: Calderon-Margalit
authors.affiliation: Braun School of Public Health, Hebrew University-Hadassah School of Public Health, Jerusalem, 91120, Israel.|Department of Sociology, Princeton University, Princeton, New Jersey, 08544.
authors.forename: O
authors.initials: O
authors.lastname: Manor
authors.affiliation: Braun School of Public Health, Hebrew University-Hadassah School of Public Health, Jerusalem, 91120, Israel.|Department of Sociology, Princeton University, Princeton, New Jersey, 08544.
authors.forename: O
authors.initials: O
authors.lastname: Paltiel
authors.affiliation: Department of Sociology, Princeton University, Princeton, New Jersey, 08544.
authors.forename: D
authors.initials: D
authors.lastname: Conley
authors.affiliation: Department of Psychiatry, New York University School of Medicine, 1 Park Avenue, Floor 8, New York, New York, 10016, USA.
authors.forename: S
authors.initials: S
authors.lastname: Harlap
authors.affiliation: Department of Psychiatry, New York University School of Medicine, 1 Park Avenue, Floor 8, New York, New York, 10016, USA.
authors.forename: D
authors.initials: D
authors.lastname: Malaspina
mesh_terms: D002947:Cities; D015331:Cohort Studies; D005006:Ethnicity / Q000706:statistics & numerical data*; D005192:Family Health / Q000706:statistics & numerical data; D005220:Fathers; D005843:Geography; D000066502:Grandparents; D006801:Humans; D007557:Israel; D050498:Live Birth; D008297:Male; D008877:Middle East; D011157:Population Dynamics; D012189:Retrospective Studies; D012744:Sex Ratio
keywords: ancestry; birth cohort; sex ratio