I don't remember where I saw it. I don't remember if it was in one of those DC Annual events like the Waverider thing or what... but this is it:

Barbara Gordon gets a Green Lantern power ring. I don't recall exactly the circumstances, perhaps Guy Gardner flipped his lid and it was confiscated.

Can anyone tell me what issue this took place in?

JLA: Created Equal.

What were the circumstances in that story?

I think all the men on earth vanished/died/were incapacitated, and the women of the DCU had to rescue them.

I've got it. Haven't read it in years, but some kind of space virus killed all the men on Earth. Only Superman was immune, and Lex Luthor also survived due to the fact that he had sealed himself inside that green & purple suit of armor. So all the superheroines had to try to help run the planet and maintain order. Some supervillainess had taken Kyle's power ring, and so the heroines teamed up, took it from her, and gave it to Barbara, since she was more worthy.

I won't spoil the rest of the story, but it involves using Superman's super-sperm to help repopulate the planet via mass invitro-fertilization.

I just bet it does.

Superman had an almost identical solution to the problem.

And then Wonder Mike from the Sugarhill Gang repopulates the earth with his super sperm.