A more thorough explanation:

A genetic father is a male parent who has contributed his genetic material to the conception of a child. This is also known as a biological father.

For example, if a man has a child with a woman, he is the genetic father of that child because he has provided half of the child's genetic makeup.

Another example would be a sperm donor who donates his sperm to a fertility clinic. If that sperm is used to conceive a child, the donor is the genetic father of that child.

These examples illustrate the definition of a genetic father because in both cases, the male parent has contributed his genetic material to the conception of a child, making him the biological father.