The words “kin”, “knee” and “gynaecology” are all related. It does not appear obvious at first sight, but think about the pronunciation, particularly the original as guided by the spelling, and it becomes more obvious.
“Kin” and “knee” are both basic Germanic words and, of course, the latter was originally pronounced with the leading “k-“. Add that in, and it is easy to hear that they sound alike. They are, in fact, from the same root.
“Gynae-” is a prefix from Ancient Greek but ultimately from the same Indo-European root as “kin” and “knee”. The initial hard “g-” is merely a voiced “k-” (or the other way around, depending on how you want to look at it).
Why would a word referring to family linkage (“kin”) be linked to a word referring to a part of the body (“knee”) and to a word indicating female (“gynae-“)?
Easy. The ancient Indo-European women (“gynae-“) gave birth (to their “kin”) on their “knees”. All three were obviously linked, therefore, and language supported that.
Ugh! But this is backed up by historical references, from the Bible to Roman scrolls suggesting that giving birth on knees is humiliating and should be stopped (and thus was still the norm, at least among some).
Never doubt the power of linguistics – or the desirability of social advances!