Description : If my half sister had a baby what is it to me?
Last Answer : Technically, the baby would be your half-niece or half-nephew, and you would be their half-uncle or half-aunt. But many people dislike the term half or step (I have two stepsons and one natural son) and ... the term half or step. So I'm with C3 Shooter on this, treat them as your nephew or niece.