There is a nice article that confirms what Farm boy states:
http://www.payscale.com/gender-lifetime-earnings-gap
According to data in the article college-educated women hit their pay glass ceiling at age 39 with an average salary of $60,000, whereas men's pay stops growing at the age of 48 with an average salary of $95,000.
It also says that a lot of this has to do with job choices: "Overall, men and women gravitate toward different careers. The most popular choices for men tend to pay higher than the most popular choices for women."
When we compare men and women salaries in similar jobs and experience the pay gap is not that big: amounting to a mere 4%
There are also very nice charts, here in spoiler due to the dimension:
In the linked article you also have a large explanation about the methodology used.
More important for this thread (about parental leave) the graph shows that in USA college educated women's pay stop outpacing men's at about 30 years of age: exactly when they start having children.
There is no doubt that having children have very considerable consequences for the women careers, especially in USA where they have limited support for parental leave.
(paid) maternity leave helps to alleviate this problem.
Forcing men to take paternity leave (as in Norway) helps even more to make the odds more fair: in this context also men have to take a pause in their career progression when having children.
I do not have data about Norway (I did not search, sorry) but it looks to me that paternity leave helps considerably to make the "playfield" more fair for both genders.
Yes indeed!
Having a leave from your work always have a considerable effect on your career progression especially in comparison to those who decide to don't have children (thus continuing to progress in their work).
A
paid parental leave, again, helps to alleviate this gap.
On a side note, we shouldn't evaluate the merits of parental leave only looking at their effect on equality on the work place.
One of the main targets of (paid) parental leave is to make people leave better lives, so that they have the opportunity to enjoy a very important time with their children without having to suffer for it.
It's also a way for the state to don't place people in the difficoult situation of choosing between job and children: the policy is meant to stimulate people in career to have children.