The fetus imprints its mother's voice. Searching for that brings up lots of relevant links, such as How a mother’s voice shapes her baby’s developing brain, https://aeon.co/ideas/how-a-mother-s-voice-shapes-her-baby-s...

Some children are fine after getting adopted. Others have issues. For example, the adoptive parents of the recent Florida school shooter tried to get their adopted son help, but he never did well, and apparently completely fell apart after his adopted mother passed away.