Your point is valid, in certain parts of the world, some couples get officially married after they had 2 kids! The examination would not be necessary.

But there are many other countries where such physical contact only happens after marriage.

But expats in those countries might be required to run pre-marital test. Check what I found.

http://www.khaleejtimes.com/DisplayArticleNew.asp?xfile=data/theuae/2007...

Salaam