This is a question posed to the Facebook group on Evolutionary Psychology. Most participants seem inclined to the latter answer.
My own answer:
Human nature being that of a social animal, all biology is mediated by social constructions. This is especially the case as regards socially organized and mythologized roles such as gender. You mean there are biological differences such as can be studied by anatomy, biology, etc.? Sure enough and not to be questioned. But anatomy and biology will not provide you with a full understanding of the complexities of gender behaviour, representations, etc., and you have to go to the social sciences and the humanities for that. I.e., gender is indeed a social construction or imaginary reconfiguration of biological differences.
That said, there is no consensus anywhere on any subject whatsoever. You have to choose the community of cognoscenti you are going to trust.