Great post!
I personally believe that every human behavior is influenced both by the individuals biology as well as social factors. That includes their identity and who they become in life. Basically it comes down to how the individuals genes interact with their environment. Its funny how people in different fields often tend to believe that these things are attributed to either the individuals biology or their social environment though - as you pointed out with your colleagues. Some people believe that it is an either or scenario. But I dont think that we can say that these are either or scenarios personally. They will always be both. Genes definitly play a huge role in a individuals behavior and interestingly, different environments can activate and influence different genes.

I find the topic of attachement pretty interesting, especially since research suggests that an individual's attachement style carries with them into adulthood but also that a secure attachment style can be learned and developed overtime even in adulthood. I wasnt aware that genes play a role in that as well. That was really interesting.

The part that you discuss regarding sex hormones in utero influencing gender is quite interesting as well. I only have a limited understanding of that but find it quite facinating. It seems that even birth order may have an effect on that as well as sex hormones can change and be influenced by previous pregnancies. Kind of like a countering effect. Again, my understanding of that is limited though. And as you pointed out, socioeconomic factors also often play a role in an individuals behavioral development (if im understanding correctly).

I personally think that the moral of the story (so to speak) is that in the end, both biology and social factors influence an individuals behavior and identity. I dont think that we could ever truely rule out either.

Hopefully HF21 goes smoothly.
Take care :)