To think men should be the ones wearing make up

[FiveLittleSpeckledFrogsSatOnAS]

if anyone should as a social norm?

In lots of species, the males are more colourful and attention grabbing. If you look at lions, ducks, birds of paradise, baboons, or peacocks for example, they all have far 'prettier' males and 'plainer' females.

So why do a lot of cultures expect females to make themselves "prettier" with make up, but not expect males to?

I think they do- not with make up, but I know my teen nieces expect a boy to work out and look 'strong'. I suppose that is a kind of version of make up. Also, with a lot of them, only ONE of them is actually doing the picking, mainly. In humans, the woman and the man are (usually in the UK) picking each other, so it's not one sex attracting the other, it's both of them attracting each other.

Sorry, didn't write that well. With most of those animals, one gender will be mating with any of the females they can get, so the picking is more one sided than with humans, usually.

Back in the 13th century men were the ones who dressed up, women wore boring shit - like the modern day male jeans and t shirt uniform. So it goes.

According to Tyger (yes, really spelled that way), who is none other than Ben Dover's son, there is actually a growing trend for men to wear make-up. He did a series on BBC recently and one episode has men waxing and tanning and apparently ''becoming more feminine than the ladies'' they clearly don't know the half of it yet
I personally look around the high street and see a lot of women who make an effort with clothes/hair/make-up/hygiene and a largely overweight/badly dressed/leery menfolk. Not all, but largely. It is amazing how many men over 40 seem to think they have the right to let themselves go completely and yet expect wives to stay looking in their 30's.

As a big fat hairy HGV driver in his 50s, I moisturise daily, trim stray hairs and have been known to use Dove Glow on my revoltingly white and horribly scarred legs when shorts become necessary.

This isn't adornment, more of a public service for people who might have just eaten.

DH uses a blow dryer and a flat iron on his hair. He looks very stylish and sexy. Women aren't the only ones keeping well groomed.

With most animals, the female rears the young alone, so the male has to be attractive to get the shag. With humans, back in caveman days, the womane needs a partner around to help as the baby is helpless and takes so long to become independent, so the female has to attract the best co-parent.
This is changing now as women realise they can raise a child alone and children is not the only purpose of sex (only really since reliable contraception in the 60's) - therfore men need to make more effort.
Advertising and magazines also have thier part to play on both sexes.