u could tell by the nodes look in the midle where the stem and branch connect
when the time comes ull either see some like pear shaped sacks and after a little bit if u dont see like white hairs coming from the top of those sacks then its a male ull normally see a few sacks around each other with no hairs but if u see hair coming from the top of them then they are fem,but if u look around the plant and see both of these u could have a hermie