I don't think she's either. Here's her MK3 bio:

"She was hand picked by Shao Kahn as Sindel's personal protector. She becomes suspicious of Shao Kahn's loyalty towards her race of Shokan when he places Motaro as the leader of his extermination squads. On the Outworld, Motaro's race of Centaurians are the natural enemy of the Shokan."

So there is not one mention of being a part of Goro's family. It definitely wouldn't be his mother, her name is Queen Mai.

But I think she was just a shokan warrior, who was appointed as Sindel's personal protector.

Goro's known family members are King Gorbak (father), Queen Mai (mother), and Durac (brother.)

I always just assumed that she was his daughter. But I guess she doesn't necessarily have to be related at all.

I recall reading somewhere a long time ago that she was his cousin.

i always thought they were cousins as well.. from a long time ago

I thought I read she was one of Goro's 9 wives somewhere.

I think Sheeva is Half human and Half of Goro and Kintaros race (but i dont think you could drink Someone like Kintaro attractive). Who knows, they might also be family

Not finding Kintaro attractive? If Kintaro (Or another Shokan) wanted to get with a human I think it would be more than easy. But I also think that Sheeva is ALL Shokan. Cause the Human part would weaken her and Shao Kahn DID pick her out of all of them.