The average wage of women starts falling behind that of men at around the age of 30-something, which does match the point when people have kids nowadays, especially women with higher education. Funnilly enough, in average women earn more than men up to that point because more women get degrees than men.
So yeah, it’s related to childbearing.
However…
It apparently depends on how long a woman stays away from work during the parental leave period: the longer that happens the bigger the negative impact on a woman’s career and hence her on lifetime earnings.
Part of the reason why mothers stay much longer at home on parental leave than fathers are indeed personal choice, but part is cultural (i.e. societal expectation that the mother takes care of the children), part is legal (different legal lengths of parental leave for men and women) and part economic (insufficient provision of affordable kindergarten places, at times making returning to work more costly than staying at home, which associated with the other parts means women are the ones that more often end up staying at home for years after childbirth due to this).
Whilst the first 2 aren’t really something governments can do much about, the other 2 are.
A handful of countries have gone ahead and done things to change this, for example with free kindergarten places guaranteed for every child and parental leave which is just one big gender-independent block of months that can be divided between parents in any way they see fit.
So are these female politicians in Iceland pushing for the real world solutions that can start fixing the roots of the problem or are they just endlessly posturing about the symptoms for image management and political gain amongst the majority gender?!