Frank,

The fact is woman get paid less than man in the same position. Yes even in IT, some programmers do database programming, some programmers do web programming.  But if a man and a woman does same web programming job, the woman would get less pay and that is the fact, even the bureau of labor admitted it.  The pay scale is so complicate for a lot of company, if you complain, they can say a lot of things. 

BTW staying at work for 45 hours does not mean you work 45 hours.  Some people spends time smoking, talking, and do other things.  Working 42 hours does not mean the woman does less work.  Maybe she is more efficient.  One of my co-worker spends a lot time at work because his programming skills suck, he cannot figure out how to do the job.

You said why companies did not hire women if they got paid less, it depended on the job.  As I said only 28% of women in IT business, how can a company hire all woman when no woman resume comes in.  On  the other hand, women are the majority in nursing and teaching. 

I worked in 10 ten companies so far, at least 3 of them I was the only woman on the team. (A team of 10 to 15 people).