Excerpts from Statistics Canada article: A sizeable earnings gap exists between Canadian women with children and those without children, but much of this gap can be explained by differences in work experience and other characteristics. During the period 1993 to 2004, average hourly earnings of women with children were 12% below those of women without children. At younger ages, the gap between women with and without children was quite small. At the age of 20, for example, the earnings of women with and without children were $8.60 and $9.50, respectively (2004 dollars), a gap of 10%. At the age of 30, the gap widened to 19%. Although it shrank slightly between the ages of 34 and 38, it widened further thereafter. For example, at age 40 the gap became 21%. Much of this widening gap can be attributed to the career interruptions of mothers. Women with children had almost a six-year difference between their actual and potential work experience, while women without children had a disparity of just above one year. Long career interruptions had a strong negative impact on the earnings of mothers. For example, the difference in average hourly earnings between childless women and mothers with more than three years of interruption was close to 30% at the age of 40. Among mothers with different lengths of interruption, the gaps were significant only for mothers who had more than three years of interruption. … The gap was also related to the number of children: it was fully explained for mothers with one child but remained significant for mothers of two or more children. The earnings gap between single mothers and single childless women was almost twice as large as that between married mothers and married childless women. Once other individual characteristics were controlled for, the gap for married mothers disappeared, while that for single mothers persisted. Well-educated (more than high school) mothers incurred greater earnings losses than less educated mothers. This was still so even after controlling for other individual characteristics. … But persistent gaps for certain groups of mothers were still evident. In particular, lone mothers, mothers with three or more children and highly educated mothers incurred greater losses than married mothers, mothers with one child, and mothers with less than a high school education. - reprinted from Statistics Canada