Genital organs (development)
Up to the 6th week of pregnancy (SSW), XX (female sex determination via genes) and XY (male) embryos are identical. After the 8th week, the testicles of the XY embryos begin to produce testosterone. This causes the male sex organs to develop.
In addition, the organs develop in the 3rd to 8th SSW, so that this period is the most susceptible to malformations. This can be important for the medication.
After the 9th week all organs are developed and sex differentiation has begun.
https://de.wikipedia.org/wiki/Geschlechtsorgan (Wikipedia CC-by-sa-3.0)