There isn't a specific month where most girls are conceived. The sex of a baby is determined by the sperm that fertilizes the egg, not the month of conception. While some studies suggest that the time of year may influence the ratio of male to female births, these findings are not conclusive and there is no proven correlation between the month of conception and the sex of the baby.
The sex of a baby is determined by the chromosomes in the sperm. A sperm carrying an X chromosome will result in a female baby, while a sperm carrying a Y chromosome will result in a male baby.
