A reasonable man is likely to take offense at comments about a female colleague's menstrual period.
(the scenario is a female rummaging in department cupboards, male asks what's wrong, female says her PMS is bad and she's in need of an aspirin. Verdict = harassment)
WTF?!?! it is a perfectly natural part of being human, there's nothing offensive about it.
this is why we can't have open honest communication, and why we utterly fail to get along as reasonable adults. The law forbids such.