Release date is 2026-04-20

Tim Lindell and the Online Distributed Proofreading Team at https://www.pgdp.net (This file was produced from images generously made available by The Internet Archive)

Sex at Choice by Mrs. Monteith Erskine is a medico-social treatise written in the early 20th century. Aimed at women, it argues that mothers can choose the sex of their children by timing conception within a 28‑day “lunar month” and by exploiting the supposed alternate action of the ovaries (right for boys, left for girls), framing this as both practical guidance and a eugenic good. The work blends personal case records, anatomical description, and social commentary to promote sex pre-determination without birth control.

The opening of the book presents a lengthy preface in which the author recounts decades of observation leading to her central claim that sex is fixed before fertilization and is determined solely by the mother, tied to an alternating right/left ovarian cycle and specific fertile days. She dismisses diet, parental age, and animal analogies, embraces “lateral decubitus” traditions, and argues for timing within the lunar month, positioning her method as a humane alternative to birth control and a tool for eugenic selection. An introduction by her husband endorses the publication after years of reticence. Early chapters mix social advocacy and instruction: calls for more male births, infant-welfare measures (especially breastfeeding and circumcision), use of incubators for premature babies, and warnings about miscarriages (claimed mostly male), illegitimacy (claimed to yield more girls), and the effects of drink. She offers anecdotes on sterility “cures” via precise timing and rest, links menstruation patterns to likely offspring sex, outlines basic female anatomy and the “alternate working” of ovaries, and begins practical rules “for a boy,” favoring conception around days 8–15 (especially day 12) from the start of menstruation and only in alternate months. (This is an automatically generated summary.)

Originally published: New York: G. P. Putnam's Sons, 1925