Universities
 

Anyone has been to both a Japanese and a North-American university and is willing to share their impressions ?

I've heard the women/men ratio was pretty low.

I`d say that depends a lot on what university, and what you`re studying. No different than outside Japan.
I think the larger difference is that there are so many smaller universities that specialize in certain areas - rather than being quite as mixed as those in the US.
So, chances are, if you head to a university specializing in science, you`ll find there are more men than women. Head to a different university specializing in arts - the other way around. The universities I went to were fairly balanced. Most people do go on to college, regardless of gender.