Some quotes from the article:

"One of the worst career moves a woman can make is to have children. Mothers are less likely to be hired for jobs, to be perceived as competent at work or to be paid as much as their male colleagues with the same qualifications."

"Ms. Budig found that on average, men’s earnings increased more than 6 percent when they had children (if they lived with them), while women’s decreased 4 percent for each child they had. Her study was based on data from the National Longitudinal Survey of Youth from 1979 to 2006, which tracked people’s labor market activities over time. Childless, unmarried women earn 96 cents for every dollar a man earns, while married mothers earn 76 cents, widening the gap."

http://www.nytimes.com/2014/09/07/upshot/a-child-helps-your-career-if-youre-a-man.html?referrer&_r=0&abt=0002&abg=0