Instead of talking about whether or not some contentious category regarding human biology is a "social construct," people should instead use "loose heuristic" or "tight heuristic." It would clear up what seems to be a great deal of confusion. As it stands now, "social construct" is a bait and switch. When reasonable people use it to concede that something they study is indeed a "social construct," they are usually saying that the lines are drawn somewhat arbitrarily, but there are legitimate biological underpinnings.