Also Mazinger (may be known under a different name in some countries). One of the robots (Aphrodite A) had titty missiles: https://tenor.com/en-CA/view/afrodita-aphrodite-mech-anime-gif-16897967

I accidentally downvoted myself.

This might be pseudoscience I got taught 20 years ago, but I have been under the impression that human evolution of breasts as a secondary sexual characteristic has to do with the shift to becoming bipedal. Like a lot of animals, early hominids would see the rear end of a fellow hominid and know this as a trigger for copulation. But when homo erectus started standing upright, butts weren't so universally erotic anymore. They had a whole back and head above them now. Breasts didn't need to be very large to fill their function, but an increase in size gave them a curvy appearance similar to a set of butt cheeks. And early humans were like, yeah, I think that's right, and selected for increased (or at least variable) breast size.

I'm not aware of any other species sexually selecting for mammary size. Some birds do a puffy chest thing.

It might be a learned association rather than anything instinctive about tiddies. There's this one study where they gave rats a backpack fetish, but it has a sad ending because then they murdered all the rats. They did phrase the murder like they were doing a Satanic ritual though, and that kind of took some of the murdery edge off it for me.

I've been looking forward to like 20 years from now when all the incels will be into girls with too many fingers.

Tiddy loving might be a cultural thing. Human species that don't need clothes care little for the boobs. Though they live south, so either they are used to it or it might be Neanderthal(or other varieties) genes that some of us inherited. We certainly are boob fetishists among the mammals.