mother gives birth to a child, and also gives birth to her mother.
Especially the first child. She was not his mother but 'mother' before she was born. Maybe there was a daughter, there was a darling, a sister or a wife.

If you are the first child, then you have given birth to your mother. He can go and say, if you do not have me (mother's rights) would not have been born !!

Happy Mother's Day!