During my BS work in biological sciences, we were told of an experiment. Twenty women from around the world were asked to ID their husbands by smelling a shirt. They were able to pick which shirt their own husband had worn. Also, widows sleep in a shirt worn by their husband that still carries his scent. My husband (we are recently both remarried, me 40s, him in his 50s) has a particular spot in his right armpit that has a definitive scent that absolutely drives me crazy. I think the first time I sat beside him, I must have caught his "pheromone" scent!