Yerno (Spanish for “son-in-law”) at first sounds like nothing in English.
But let’s look closer! The g- and y- sounds are often mixed up between languages and even regions that speak the same language; in fact, the Old English g- transformed itself into a y- over time (compare the German gestern with the English yesterday, for example). And the n‑r sound not uncommonly swaps to become an r‑n sound, the two are easily mixed up, especially in slurred speech.
Thus, the bizarre-sounding y‑r-n root of yerno maps to the g‑n-r root of generic (Maybe sons-in-laws are more generic in Spanish cultures than English ones?) as well as genus (which lost the final r-) — yes, genus as in Latin and now scientific classification of your spot in the universe! The son-in-law, I guess, is destined to be the son-in-law as his lot-in-life.