"Truth be told, how do you expect to know if a person is a man or a woman even when they say they are?"
The topic of this thread provides a remarkably effective way to do that. If someone refers to breasts as "boobs", "tits", or other similar names, it's most likely a man. Women tend to simply call them breasts.
That is because we go to the Doctor and have Breast Exams, Breast Mammos, Ultrasound, wouldn't it be funny if the doc said please come in for your annual Boob or Titt exam! HAHA