Carson Kressley says gays check every applicable box when it comes to donating blood ... and that's why it's time to change the law restricting them from doing so.

The ex-'Queer Eye' star was in Bev Hills and told us he's proud of his pal, Lance Bass, taking a stand on the issue of gay men donating blood. Carson's on board with Lance's movement, but had a little more to say.

He laid out everything the gay community has to offer blood donation centers ... besides blood. For Carson, changing the FDA regulations will be a serious win-win-win!!!

IT'S A SHAME
TMZ.com