Should you be surprised that those with less work experience get paid less?

TD Economics says mothers who have taken time off for parental leave face a consistent wage gap of about three per cent for every year of absence. The difference is proportionally more severe for mothers who have taken multiple leaves.

... Depreciation of skills is thought to be one factor why mothers who take parental leaves would see smaller salaries, TD said. But economists behind the study also said employers are using the frequency of parental leaves as a signal for how committed women are to their jobs.

Source: The Montreal Gazette

The article also cites TD deputy chief economist Beata Caranci as saying that "The research leads us to conclude that exits from the labour force — most often related to family or motherhood, not gender — are the culprit behind this unexplained wage gap". Yet, I'm not sure how that fits with another study that claims that

Women are more likely than men to leave the labor force within every age cohort. Furthermore, women are more likely than men to leave the labor force for reasons other than family within every age cohort. Therefore the conventional explanation that these differentials in exit behavior are a result of childbearing by women is incomplete.

Source: Anne E. Preston, Why Have All the Women Gone? A Study of Exit of Women from the Science and Engineering Professions, The American Economic Review, Vol. 84, No. 5 (Dec., 1994), pp. 1446-1462

A later article notes that any wage losses actually disappear within a few years, something that I actually find to be a little bit surprising given the comparative lack of work experience in whatever profession they were engaged in. (This isn't intended to claim that being a stay-at-home mom isn't work - it is - but rather that this type of work likely differs quite a bit from the sort of employment that they'd be engaged in outside the home).