The term “sex” and “gender” are often used interchangeably.
Conclusion (implicit)
"Sex" and "Gender" should not be used interchangeably.
Evidence
Sex = biological differences between male/female Gender = society's construction of what qualities are masculine / feminine.
Sex sorts people into two nonoverlapping groups (those with a Y-chromosome, and those without), whereas gender doesn't sort cleanly into groups. You could have some combo of masculine and feminine traits.
Evaluate
The question stem here is not a typical "Find the Conclusion". It curiously says to find "a" main point.
In general, when LSAT has used the term main point rather than main conclusion, it has meant that we can / should think a little more holistically.
It has sometimes meant that they're testing an implied conclusion. It has sometimes provided us with a correct answer that actually summarizes the Conclusion and Premise.
Since the conclusion on normal Main Conclusion questions is typically found in the first sentence or as part of a rebuttal, it makes sense to slow down and place a lot of emphasis on the "But" that begins the second sentence.
Is there a point of view before the "But" that the author could be rebutting?
Yes, it seems. The behavior of using "sex" and "gender" interchangeably seems to be something the author is pushing back against, so we can write our own implied conclusion that the author is saying "don't do that".
Goal
Even though I would consider the main conclusion, I would stay very flexible in thinking about these answers since the question stem asked "what's a main point", not "what's the main point".