Saucy Santana is sharing his thoughts on the ongoing debate over transgender women competing in women's professional sports ... calling on the WNBA to make a decision.

We got the rapper in New York City and asked him about the possibility of trans women playing in the WNBA ... and he told us, "trans women are women."

We dug deeper and asked whether a trans woman should be allowed to play in the WNBA ... and Santana told us he believes that decision should ultimately be left to the league and its eligibility rules, which aren't clearly defined.

If Santana were running the WNBA, it sounds like trans women would be playing.

But he's not ... and the WNBA came out last night and slammed "bad-faith efforts" by former NBA players Enes Kanter Freedom and Royce White to enter the WNBA Draft by claiming they are trans.