In my linguistics textbook (6th edition of "An Introduction to Language"), the "Language & Society" chapter tells me that:
Some languages have no native words to mean 'sexual intercourse' but do borrow such words from neighbouring people. Other languages have many words for this common and universal act, most of which are taboo.
I'm deadly curious, what languages are we talking about here that have no native word for sex? I find this incredibly strange, considering its (as the book says) universality.