I hope no one takes this one as sexist..
I used to have this job in the mailroom of a company. I had a daily run and saw the same people every day. I noticed something interesting about one girl on the run. Every few weeks, it seemed, I noticed a certain aroma in her office. I didn’t have to think about what it was, my brain just KNEW it was that she was having her period. It would be there for a few days and then gone for a few weeks again. I didn’t think about it outside of work, or really even in the weeks between, but when it was that time again, I instantly knew what it was as soon as I smelled it. This kind of freaked me out a little since it had never occurred before.
Since then it has happened on occasion at a store or restaurant. I walk in and smell it and can immediately tell which woman it is coming from, just looking around the room. Is this normal? Is it just a pheromone issue? Or did I not evolve with the rest of the humans?