What determines if a human baby is male?
If having a penis!!!
Sperm is neither male nor female, it is a single cell - the egg determines whether the baby will be male or female. The sperm is the male sex cell, and it has two chromosomes ..... one "X" chromosome and one "Y" chromosome. Females have 2 "X" chromosomes. If the male sperm fertilizes the female egg with an "X" chromosome, the resulting baby will be a girl, but if the male sperm fertilizes the egg…
The father's genetic contribution determines the sex of the baby. Women have XX chromosomes, men have XY (this is part of the definition of female and male). The male provides either X or Y to the woman's X. So if the man donates an X, the baby is XX and thus female. If he donates a Y, the baby is XY and thus male.