Posted this a few months ago in what appears to be an identical thread, but here goes..
"I've never been asked, or instructed, to examine myself; but 10 years ago one nipple (left side) had a cyst back in the ductwork somewhere that caused tenderness/mild pain in the nip, and an occasional discharge. The MD who checked it out initially did a breast exam both sides, pinching the nipples hard (there was nothing erotic about this, maybe in another setting) and carefully went over both pecs and into the armpits looking for lumps.
While he was working, was telling me about male breast cancer - said men are about 5-10% of the reported cases, and it can be fatal more quickly because 1.) too many (including some in the medical profession) don't look for it assuming that men can't get breast cancer, and 2.) having less breast/pec mass, once a cancer appears it tends to spread more quickly into the body, doesn't have as far to go. Women have an advantage there to a degree, more cushioning, more time for discovery.
** Side trip: Male Lactation - while I was checking out my own situation and finding out that men and women are mostly identical ABOVE the waist, I ran across numerous accounts of men breastfeeding their children. It's rare, but evidently does happen; supposedly it takes much time to induce but the credible source below outlined guys (several in remote locations like a missionary would be), whose wives had died or dried up at childbirth and the husbands were able to take over nursing duty.
The balance of power between the sexes could change if that got noised around, ("Dear, it's your night to get out of bed and nurse the kid!") What will you pay me to keep it quiet?"
https://www.scientificamerican.com/article/strange-but-true-males-can-lactate/