In western culture, my experience has been: When you tell some acquaintance you're a software developer, engineer etc., they are almost instantly bored.

Contrast that with

* Science - The flair of knowledge, curiosity, discovery and a general sense of meaning

* the law - Status and money

* Medicine - Making a real difference in peoples lives, also extremely prestigous

Maybe men are just less capable of resisting the urge to tinker in order to achieve more respected/better payed jobs?

It bears to be repeated: This is western culture valuation, might be different in other cultures, which also might result in a different distribution.