Sokka and Suki were not Fire/Earth benders and didn't have any relations to those sort of benders.

First off, on Korra, we don't actually know that as far as I know, but Katara's Mom was a water bender.

Second, as I just responded to Epicpedo, you need bender genetics in your genes in order to actually give birth to a bender.

No, Katara's mother said she was, so that the Fire Nation wouldn't take Katara for being a waterbender.

And no, it's not genetic. There is tons of evidence of it being spiritual reasons, not genetic.

Why do you have to be a bender to have bender children? Its like saying the Avatar's children will without a doubt be another Avatar. There is nothing that says Non-Benders can have Bender children.

They do not have /relations/ to the bending types. You need to have Earth Benders in your genetics in order to have Earth Benders. Yes, you can have Non-benders giving birth to Benders but not if their entire line is literally ALL Non-benders. The "Bending" gene can't magically appear in their DNA.

Katara*
But what I'm trying to get at thought is the fact that you don't necessarily need bender parents to be a bender child. Maybe it's like the Avatar cycle, since Suki and Sokka fucked and they were both non-benders they had a 20% chance of a bender child and or a non bender.

Alright, Sukis ancestors are earth benders (I'm guessing), and Sokkas are water benders... ?

You're parents or grandparents have to be benders, it's an allele. Katara's mom is a bender, but she said Katara was not. Aang and Katara can only haveWater and Air.

Sokka's mom was water bender, maybe they would have a water bender but. but Suki's parents were not earth benders.
So Sokka and Suki can only have water or non benders. Not Fire or Earth.