both
Through their maturity levels and their genitalia structure. Gender is determined by chromosomes A male has an X and a Y chromosome. a female has 2 X chromosomes
Because of the hormones they produce.
mama cells and daddy if mama give you more than dad you are a girl if dad give you more than mom you are a boy
They just say what comes first alphabetically. "B" comes before "G" so it's boys and girls club.