It’s a male or a female in my garden ?
If you have chosen to grow Regular seeds, then you will have to remove males, unless you want to produce your very personal seeds. Males are not that bad if it's taken from the good side. At least don’t trash them, make yourself a smoothie !!
Pre-flower will discreetly show themselves after 2 month of vegetative growth. It’s a bit tricky to see them at that time, but it’s interesting to be able to make the sexage before the flowering phase.
Under a lamp, the first flower will appear after 1 or 2 weeks from the changement of photoperiod.
To find the flower, look very closely at the node, at the exact starting point of the petiole. If a white (or colorful) pistil shows up, it’s a female !! On the other hand, if it looks like a green (yellow or colorful) little ball, then it’s a male… First flowers always appear on a node on the main stem, usually 2 or 3 nodes under the apex. Check this area, but also check other branches and most nodes on it.
Why not keep one smelly/good-looking guy to produce some seeds. It’s possible to pollinate just a branch and produce a few seeds instead of turning your whole crop into seeds.