system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: do average vaginas correlate with the ethnically average penis size?
gpt
Vaginas do not have a set size. They all have an ability to change shape, and like the way men get erections, they expand, lengthen, and lubricate when the woman is aroused. 

So to estimate the female capacity to accommodate a penis, just look at their body size. The average Asian woman is also smaller. narrower hips, often shorter. Meaning a correlating shorter length between her vaginal entrance and cervix.

At the same time, A tall, wider hipped woman doesn't have a gaping hole, but she can probably comfortable stretch further than a smaller woman, because her body has the room to stretch. 

When not aroused a vagina gets pretty small, and tight. and even when aroused and engaging in intercourse, it usually hugs the penis snugly.

Its made to adapt. But of course with evolution they haven't really caught up with the size of babies heads. The damage that can be done during childbirth can affect the vaginas ability to shrink back.