so THAT's where the male/female ratio comes from

From the WTF? department: the Sunday Times is reporting on a study that indicates that people in traditionally male-dominated fields like engineering are more likely to have boys than girls, while people in traditionally female-dominated fields like nursing are more likely to have girls than boys. The study apparently describes people as "systemisers" or "empathisers" (yes, with an "s" -- it's a British paper) with the result that "systemisers" tend to produce male children and "empathisers" tend to produce females.

The article also includes this gem:

A study published in 2002 by the University of Auckland, found that assertive women had a higher chance of having a son because of their testosterone levels — indicated by long ring fingers. Meanwhile, Copenhagen researchers have found that smokers are more likely to have girls than boys.

Much teasing ensued around the household regarding the length of one's ring finger.