Big men, small women

I was chatting to a Malaysian friend who transferred to a US university for his studies. I fixed for language.

FIS says:
But I now feel more liking for American girls lor

Me says:
Why?

FIS says:
For no reason

FIS says:
I don't know

Me says:
Are their girls (American) much taller and bigger?

FIS says:
Not really

Me says:
But why are their guys so big then?

FIS says:
Haha


This is weird. My dad is tall, at least half a head taller than me. My mum is short, at least half a head shorter than me. I'm relatively short and I've always thought that this is the case because I had partially inherited short genes from my mum.

Americans (at least their men) are generally bigger in size than Asians. But if their women are actually much smaller, then the height of their population is supposed to converge to a value between the height of their men and women. So since their women are not that big, their men shouldn't be that huge.

But their men are big.