Quoting @ultraviolet who made a comment about this earlier:

This “debate” is usually framed in the context of “biological advantage” because it is true that top male athletes have an advantage over top female athletes so they believe that trans women (who are assigned male at birth) will have an advantage over cis women. However most top competitive sports (like the Olympics) have rules requiring the trans person to be on hrt for some time. Trans women who have been on hrt for a few years really have no biological advantage over cis women. Now some might resort to arguing that hrt does nothing to bone length (which is mostly true for trans women who started hrt after puberty) but then you don’t see them complaining that a cis person is being unfair because they were born with longer legs or anything like that. Furthermore the concern trolls seem to only come out whenever a trans person wins any event and they forget the times that trans athletes finish in 4th, 5th, etc. so they seem to only think it’s “fair” when a trans person loses.

You can also ask them to name a top female athlete. Chances are they will be a cis woman (or they can’t do it because none of them give a shit about women’s sports unless they can use it to hate trans people.) If trans women really were dominating then they should have disproportionate representation which is not the case.

Outside the top competitive events it gets really silly, like are you going to foam at the mouth because some local recreational league lets people of all genders participate? While it is true that top male athletes outperform top female athletes, there is a lot more variation in an “average” person so it’s really dumb to assume that a trans woman always has a “biological” advantage over a cis woman.

At the end of the day, if you care about “biological advantage” so much, then you should be advocating for more resources for young trans people (like puberty blockers) so they never have to go through the wrong puberty to begin with (and suffer a lot less dysphoria) but these people who yell about biological advantage never cared about trans people to begin with.

Edit: There was a whole thread about this earlier peep on the deets there if you want more.