Genes responsible for sex determination work in the early months of pregnancy:
Because if the fetus:
- The chromosome (Y) begins six weeks after the beginning of pregnancy in the production of hormones under the tissues of the (undifferentiated) to form the testes and then distinguish the rest of the male genitalia.
- Does not carry the chromosome (Y) begins 12 weeks after the beginning of pregnancy in the formation of ovaries and then distinguish the rest of the female genitalia.
Because if the fetus:
- The chromosome (Y) begins six weeks after the beginning of pregnancy in the production of hormones under the tissues of the (undifferentiated) to form the testes and then distinguish the rest of the male genitalia.
- Does not carry the chromosome (Y) begins 12 weeks after the beginning of pregnancy in the formation of ovaries and then distinguish the rest of the female genitalia.