Prospective parents searching for means to preplan the gender of their offspring might have been encouraged by a 1974 Lancet article1 reporting a nearly 2:1 (112:58) female to male birth ratio after two years of prior contraceptive use by the mother. These hopes have now been dashed by a study of over 6,000 births that followed conception when ovulation suppressants were discontinued.2 The report leaves little doubt that the female to male birth ratio continues to hug the traditional 1:1 (3045:3064) proportion. In Boston, at least, male births remained close to 50% (between 49.1% and 51.2%) regardless of total duration of contraceptive use, interval between discontinuance of use and conception, or prior history of contraception.
Man has not yet bent the laws of probability.
de Jong RH. The "Pill" Shows No Favors. JAMA. 1977;237(14):1470. doi:10.1001/jama.1977.03270410070032