One of the amusing things of 1960s comics… bestiality and incest were just normally accepted comics ideas for stories.
The Legion of Superheroes really led the way for coming up with quite a number of powerful, equal female characters in the comics of the 1960s and 70s. No other superteam of that era even came close.
(by the way, the irony of this cover is that less than a year later, Supergirl WOULD kick the Legion of Superheroes out of Adventure Comics and take over a starring role until she finally got her first solo title in 1972.)