Riley Gaines Opens Up On Pivotal Supreme Court Cases Weighing Trans Athlete Bans

Riley Gaines is weighing in on one of the most consequential Supreme Court cases in years ... and while the former college swimmer turned activist believes this is a big moment for girls' sports, she also says much more must be done!

"There were two landmark cases heard before the Supreme Court earlier this week. One out of Idaho, one out of West Virginia," 25-year-old Gaines told TMZ Sports.

"Basically, what the Supreme Court will soon rule on if it's constitutional for states to allow for women to have these protections. Not if states must pass some sort of fairness in women's sports bill, it's on if states even can protect women's sports."

Oral arguments -- when attorneys for both sides make their case publicly in front of the nine justices -- for the two cases, West Virginia v. B.P.J. and Little v. Hecox, were heard on Tuesday ... in testimony that lasted nearly four hours.

Riley, who has dedicated her life to the cause, was in D.C. for the occasion ... but if you were expecting her to pop champagne over what looks like an eventual win for her side, that's not the case.

"Insane that, especially when you say it out loud, we're fighting for, as women, equality. It's like the bare minimum, and so it's being celebrated and applauded, and of course I recognize this as a step in the right direction, certainly. It's frustrating to me that this is something that even has to be heard before the highest court."

FYI, 27 states have laws either limiting or banning transgender girls from participating in girls athletics.

SCOTUS will decide if those laws are constitutional.

What does The Riley Gaines Show host (now available on FOX News platforms) ultimately expect from the court?

"I'm fairly certain that the ruling will be a favorable one," Gaines told us.

"Now what that breakdown looks like, I'd love to say it's 9-0, but of course that's entirely wishful thinking. I think it's likely, based off the oral arguments that I heard, it's likely to be 6-3. I think it has the potential to be 7-2."

An official decision is expected in several months.