What causes sudden behavior changes?

How much do estrogen levels differ among people of different ethnicities? What are the causes and consequences?

• Is there a meaningful difference in estrogen levels among people of different ethnicities? What are the consequences of this? Are the differing levels enough to make a meaningful difference in looks or behavior? How much? Does culture play a role if at all in causing these changes? Or is culture affected by these changes? This study talks about testosterone differences in Pakistani men vs. europeans: http://www.ncbi.nlm.nih.gov/pubmed/12608929 Related questions:

• Answer:

  You would expect testosterone to be affected by a hot climate with no air conditioning, vs. a cool climate. To test this theory, you'd need either a bunch of Englishmen in Pakistan or a bunch of Pakistanis in England. As for estrogen, I haven't heard of any differences across ethnicities. This would be easy enough to get a relative indication of, by looking at the length of cervical mucus patches. The worldwide Billings Ovulation Method of natural family planning has thousands of charts from women all over the world, so you should ask them. Not many women get their estrogen clinically measured, and the levels would vary greatly depending on their cycle day.