I really noticed that, and it annoys me. My son (20 months old) tends to wake up around 7 or 8am and around 8 or 9pm it is bedtime. So if I were to take on a "normal" job, I would not spend time with my kid at all, except for the weekends (leave house 8am, work from 9 to 6, back home 7 at the earliest). Society assumes that I am fine with that, but I am not.

Still, I'd like to add that at least in our case, in the first year the mother was definitely more important because of the breastfeeding, which really incited a strong bond. But of course not everybody does that.