Although animal research had long since shown that male sexual behavior was directly derived from this exposure to testosterone during embryonic life, this fact did not deter the pediatric practice of surgically treating male infants with this grievous anomaly by castration (amputating their testes and any vestigial male genital structures) and vaginal construction, so that they could be raised as girls. (firstthings.com)
The researchers used this live - imaging technique to study fly embryos at a key stage in their development, approximately two hours after the onset of embryonic life where the genes undergo fast and furious transcription for about one hour. (sciencedaily.com)