There are a lot of really ugly people in the real world having babies. While it's nice to imagine the best and brightest having more babies...
And, of course, the best and the brightest aren't necessarily the most beautiful, even though people tend to think they are. There have been some interesting studies to show this. Thin women, for instance, make more money than fat women. Attractive people are thought to be more intelligent based solely on their appearance, etc.
...the best and brightest are also the ones spending more time working, and actually less time making babies, or only making babies as intelligent choices with limited reproduction to match their ability to care for their children.
The more affluent, who aren't necessarily more intelligent or hard working, are definitely having fewer babies. Particularly educated women, who want to have an actual career, are waiting until their 30s to have children, and have 1 or 2 at most. I see this as a good thing, personally, since educated women are one of the things most strongly correlated with a happy society, and really, we have enough human beings in this world as it is.
Contraception is nice, but there are a lot of non-intelligent, non-beautiful, non-motivated people that don't bother with contraception, or use it very poorly.
And it doesn't help when missionaries go to the 3rd world and tell them it's immoral, or worse, lie, and tell them it increases AIDS.
I really hope the bioligist who suggested we're evolving into their dream of the ideal people was joking, because that idea is ludicrous. Breasts and hair color are genetic, but not everyone likes them big and blond, so those who prefer smaller breasts and other hair colors would be producing babies from the breast size and hair color they prefer. Six pack abs are not genetic, but the result of working out. The first is cancelled out because of people's variety of tastes, and the second is not a genetic trait.
Sadly, he wasn't joking, but he's not taken very seriously any more. Actually, IIRC, he didn't say we were *all* evolving that way, but that there would actually be 2 classes, or sub-species of human. Basically, the attractive, upper class, and the more ugly, lower class.
Of course, when we're talking about modern society, a few bucks will get you blond hair, and a few thousand will get you c-cups. 6-pack abs are more genetic than you might think, but I think you'll find them among the class of people who have the time and financial leeway to worry about getting them. And, of course, they mostly only have sex with each other, and not us fat gamers. I think that's where the biologist I mentioned was going.
Fortunately, Anima is an anime fantasy setting, and anime does not use many ugly people.
I let players choose their appearance, with some choosing to randomly roll two dice and pick the highest.
If a player chooses or rolls an appearance of 10, it fits the genre, and can be a fun plot hook as NPC's react to their appearance in appropriate ways. There can be attempts to carry off a player of either sex as either a slave or a forced marriage partner. Great looks are remarkable, and easy for people to remember when someone is trying to be inobtrusive.
My wife in one campaign has a recurring villain that is madly smitten with her character, while she is also running away from an arranged marriage. We've had both comedy and significant drama because of that interaction, though it is far from a major element of the campaign.
I honestly couldn't care any less about appearance in my RPG. It's all in our heads anyway, and we don't have to look at them. Pick whatever you want and as GM, I'm pretty much going to ignore it. Sorry, but I have enough real-life BS to deal with that I'm not going to drag more of it into my games. I'm here to kill things and take their stuff
Romantic sub-plots, although, can be fun, but I choose them based on what character types make for the best story, not who has the highest appearance.