It's been a white since I read the article, but there was an article a couple of years back analyzing the gaps in entrepreneurship for women, and the trends were:

a) smaller businesses rather than larger
b) better survivability for female businesses to the 5 year mark
c) poorer survivability for female businesses to the 10 and 15 year marks (there's those kids!)
d) greater female attrition rate (those kids again!)
e) overall poorer profitability (partly due to smaller businesses, but also type of business)

IIRC, the ratios of men to women in Canada for businesses were 2.5:1 (small), 7:1 (medium) and 13:1 (large)