The article literally talks about this. The problem is unborn children, i.e. pregnancy. That's solely a burden for the mother, who will not be able to travel and keep up with strenuous work schedules for most of the duration of their pregnancy.
Pregnancy lasts nine months and for most of that period a woman can very well travel and keep up with work. Then recovery after birth takes a couple of months (lochia, marked by bleeding, lasts a month and a half). So that's less than a yaer overall, let's say a whole year to cover cases that have a more difficult delivery than usual (although there are still outliers that will suffer problems for many years after).
So a year off work, at most. Let's say three if you want to have three children (most women in the Western world today will have one or two).
How does that square up with giving up an entire career, that lasts considerably longer than three years?
