Conception occurs when sperm fertilizes an egg found in the fallopian tube, creating a zygote that can eventually become an embryo. Conception — and ultimately, pregnancy — can involve a surprisingly ...

Adding a few days to allow for variable ovulation times, the rest of the cycle is seen as a conception-free safe period. This “egg-timer” model ushered in the rhythm method of birth control, ...

Until the 1930s physicians blithely told women that they conceived during menstruation and could avoid pregnancy by restricting coitus to other days. This, of course, conflicts directly with ...