These are the studies I was thinking of:Unfortunately, when studied in humans, there wasn’t (statistically noticeable) any difference in sex conception rates across any regular fertile time frame. The rate was still 1:1; boy:girl ratio. (There is a legitimate study for this, I’ll link it when I find it again.)
AndThe sex ratio did not vary consistently or significantly with the estimated timing of insemination relative to the day of ovulation, with the estimated length of the follicular phase or with the planned or unplanned status of the pregnancy. Although these findings may be affected by imprecision of the data, the study suggests that manipulation of the timing of insemination during the cycle cannot be used to affect the sex of offspring.
Cycles producing male and female babies had similar patterns of intercourse in relation to ovulation.
Among healthy women trying to conceive, nearly all pregnancies can be attributed to intercourse during a six-day period ending on the day of ovulation. For practical purposes, the timing of sexual intercourse in relation to ovulation has no influence on the sex of the baby.