biological mother

Her adoptive mother treats her better than her biological mother.

养母对她比亲生母亲还要好.

I'm just trying to find his biological mother.

我只是想找到他有血缘的母亲。

I could find out for you, who your biological mother and father were.

我可以为你发现，你的生母和父亲是。

Moreover with stepmother, but not my biological mother.

况且有了继母, 又不是我的亲娘.

My biological mother was a young, unwed college graduate student, and she decided to put me up for adoption.

我的亲生母亲当时是个研究生，年轻未婚妈妈，她决定让别人收养我。

He always provides for his adoptive mother as if she were his biological mother.

他一直把义母当成自己亲生母亲来赡养.

My biological mother found out later that my mother had never graduated from college and that my father had never graduated from high school.

但是我亲生母亲随后发现，我的养母从来没有上过大学，我的养父甚至从没有读过高中。