[einhverfr]

You have to distinguish between sex and gender. Gender is socially constructed, but it is a necessary social reaction to biological differences between the sexes (for example, everywhere maternity is generally biologically constructed, but everywhere paternity is socially constructed --- it is a matter of record who one's mother is biologically, but this is usually not a matter of direct record for paternity). The thing is there is a really complex relationship between biology and culture and gender itself highlights a lot of that complexity.

Add to that the fact that identity carries with it social constructs offered by society, cognitive and psychological individual factors, etc, and that this does not rule out some biological factors regarding how the individual relates to the rest of these.

So "merely" meaning to the exclusion of other factors, sure. But that doesn't mean that the social constructs might not even be at the forefront.