I concur with waterdawg, if males turned nearby females into males, we would not have cannabis at all, would we? Just a bunch of gay ass useless weeds.Female Pre-Flowers does mean it is female...but it can always turn Hermie if conditions drastically change, or if your "neighbor" is growing male plants close to you will turn them Male. Any "shock" to a plant can turn it into a hermie, including cold weather....but 70-75 temp range will not do that. 65 temp at night is fine....your all good...no need to worry..they look good.
Then you are lucky. My last crop, one turned hermie because of heat stress, it was the only thing that did not keep to a perfect environment. It was at the last stages of flower and only generated a few seeds on some of the bottom buds, so was no great loss, but it happened. Got some nice seeds out of it though and accidently created my very own strain!From my experience I have never seen a female turn hermie. I have come into operations where the power had failed and there was shell ice in the res but because the tables were up higher they did not begin to freeze yet and on the other hand I've seen it over 100F because of blower failures etc. I've done countless seeds and tens of thousands of clones over a period of many decades of course. It's either a female or a male.