I don’t know if I would go so far as to say 100% cultural. Humans have a biological basis for a lot of of our behavior, and hormones seem to factor into that. I don’t know exactly what’s cultural and what’s biological, but it doesn’t matter because women and men and people of all genders are saying they want a different, more empowering path, and that’s sufficient reason to support it.
I will say as a mother that I felt like I didn’t have a maternal bone in my body even though I really wanted to be a Mom. I had no experience with other children growing up, no idea what was developmentally appropriate, and no attachment to babies. I despised pregnancy. And somewhat unsurprisingly I wasn’t particularly attached to my own baby until he started developing his wonderful personality and I started gaining confidence as a mother. Now I’m that big goopy Mom loving on my kid all the time and doing motherly things. So I learned to do it. And I still don’t really like kids in general, just the one.
Whatever my biological orientation may have been, I figured out how to be a Mom anyway, so yes, we are all capable of learning how to do things differently. There aren’t any magic gender secrets here, just consistency of effort.