Such a child might or might not have birth defects. That depends on whether there were tendencies toward such in the family, and how strong the genetic signal might be. Even if there were tendencies, there is not certainty that a defect would show in any specific child of such an incestuous relationship.
Yes, there is an increased risk of birth defects when close relatives have children together, such as a niece and her uncle. This is due to the increased likelihood of sharing genetic traits that could lead to various health issues in the offspring. Consulting with a genetic counselor or healthcare professional would provide more specific information on the potential risks and considerations in such cases.
Your niece will call you her aunt or uncle.
uncle, niece
Your niece's children are your great nieces and great nephews, and you are their great uncle. Your uncle could be the father of your niece, and thus the grandfather of your niece's children.
A niece's son calls his uncle his uncle, just like everyone else.The niece's son calls her uncle his great uncle. He is the great uncle's great nephew.
If you are a woman, you are great great aunt to your niece's granddaughter. If you are a man, you are great great uncle to your niece's granddaughter. In either case, your niece's granddaughter is your great great niece.
You are her great-aunt/uncle. She is your great-niece.
You are your uncle's niece. You and your uncle's children are first cousins to each other.
great niece
Your sister's daughter is your niece. If you are a woman, you are your niece's aunt; if you are a man, you are your niece's uncle. Your sister's son is your nephew.
'Niece' is what a little girl is to her uncle. 'Nephew' is what a little boy is to his uncle. The children also are the niece and the nephew of their aunt.
Uncle
Your niece in-law, or your niece by marriage.