Lolo81 - you are correct. I do not have experience raising boys, but I am a long time Girl Scout leader here in the US and am raising girls. I know girls.
I saw once about a study that said in 5th grade, girls tested higher than boys in math and science. By the end of high school, the percentage of girls in STEM classes was a fraction of the number of boys. That was because society, including parents, tended to push girls into a preconceived notion around the time puberty. So I can definitely see that boys would also be stereotyped by society around that age as well.
There has been a lot of conversation the last few years about gender norms. I am all for allowing boys to play with dolls and girls to play with cars, but in the grand scheme of things no one can change the fact that as a whole, girls like pink frilly things and boys want to jump off the top of play structures. (I saw that happen once and my girl mom sensibilities almost had a heart attack). There are exceptions, of course, but we just cant change the nature of things, as it were.
As for genetics, I am always surprised to see things in my own children that are also traits of my husband or I. My youngest sleeps in the same exact position her father does and shares a lot of personality traits. My oldest looks more like me and our personalities are very similar. That is why I parent them differently. My oldest and I are very level headed and calm. I can just have a conversation with her and things are well. My youngest and my husband are sensitive and emotional. I have learned how they sometimes need kid gloves. So yes, nature is the beginning and nurture the is upbringing based on the individual needs of the child.
After all my thinking and rambling on, I have cemented my opinion that parents do not parent all children the same. I think that when we say that "I have parented all my children the same way" we may mean that we have given our children the same opportunities to succeed in life. But we never can parent our children the same because the nature aspect of them would necessitate the nurture to be different.