Natural family planning and sex selection: fact or fiction?
Determining sex of offspring by timing of intercourse has been a subject of intense interest for the lay public and professional community. This metaaanalysis of couples practicing natural family planning provides an opportunity to evaluate sex ratios in relation to the timing of conception with several parameters, including basal body temperature shift and peak mucus as markers of ovulation. Data from six studies show a statistically significant lower proportion of male births among conceptions that occur during the most fertile time of the cycle.
Gray
R H
RH
Department of Population Dynamics, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 21205.
D001831:Body Temperature / Q000502:physiology; D002582:Cervix Mucus / Q000502:physiology; D003075:Coitus; D005193:Family Planning Services / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008597:Menstrual Cycle / Q000502:physiology; D015201:Meta-Analysis as Topic; D010060:Ovulation / Q000502:physiology; D012743:Sex Preselection; D013997:Time Factors