A more thorough explanation:

A natural father is a male parent who has a biological connection to a child. This means that the father's DNA matches the child's DNA. The term "natural" is used to distinguish this type of father from an adoptive father or a stepfather.

For example, if a man has a child with a woman and they are not married, he is the natural father of that child. Even if he does not have legal custody or visitation rights, he is still the biological father.

Another example is if a man donates sperm to a woman who wants to have a child. If the woman becomes pregnant and gives birth, the man is the natural father of the child, even if he never has any contact with the child.

These examples illustrate the definition of a natural father because in both cases, the man has a biological connection to the child. This means that he shares genetic material with the child and is responsible for passing on certain traits and characteristics.