I recently had a Geni user challenge me on how I entered a profile for a child born to a single mother.
My understanding of human reproduction is that a human child is gestated from a fertilized egg inside of the mother. The fertilization of the egg can occur naturally from the sperm of the father, or artificially from the sperm of a male donor, followed by implantation of the fertilized egg into the uterus of the mother.
Regardless of the fertilization source, therefore, all children born to a single mother have a biological father. If the name of the father is not known, I enter his name as NN NN and his birth year "About" the same as the birth year of the mother.
I'd like to know what naming convention you all are using for the father of a child born to a single mother. I'd also like to know how you responded if you were challenged similarly by other users.