I understand that shifters are their own race, but I was wondering what would be the result of a unorthodox union between a shifter and an other race? If shifters are "weretouched" would their race's genetics overpower the others genetics and pass on to the next generation similar to teiflings?

I was planning on having my characters mother be human and their father be a shifter, but when I tried to look up this information, I couldn't find anything on the matter. I can just make the mother a shifter too, but humans are the most populated race in my DMs world and I wanted to keep that somewhat apart of the story. 

According to Keith Baker (the creator of Eberron, the setting Shifters were created for), yes, Shifters can breed and produce fertile offspring with a lot of other humanoid races. Typically just with Humans, Orcs, Elves, and similar races, and the resulting offspring is always a Shifter. I can't imagine them being capable of breeding with a Dragonborn, Lizardfolk, Locathah, Grung, or similar race, though. 

Thank you!