here is a pic of newly developed calyxes that swapmeet was referring to. This is what you want...the mature preflower looks identical except
way smaller...look for the hairs.
a boy looks...well different lol
you can spot a male preflower by its distinctive "claw" shape. it looks like a slightly open clam, or a cartoon crab claw, or a birds talon, depends on your perception I guess...