Why give away a baby?

Why would a Taiwanese mother in the 1970's give up a daughter for adoption?

Lately, I have been asking my students why would my birthmother give up a daughter for adoption?

Growing up with an American culture I had my own theories and assumptions:
1. My birthmother was a teenage unmarried girl who could not take care of a baby.
2. My birthmother was a prostitute.
3. Abortion was illegal.

However, hearing my students' points of view has been very eye-opening.

Often families will try to have at least one boy. The reason some families are so big is because they have three girls while trying to a have a boy. It is not uncommon for these girls to be given to other families. Some of my female students talk about the distress they felt when they heard stories of their grandparents wanting their parents to give them away to another family because they couldn't afford a 2nd or 3rd mouth to feed plus try to have a boy. So maybe I was the first, second, or third daughter and the family wanted a boy.

My brother is also adopted. Why would a Taiwanese mother give up a precious baby boy for adoption?

My students said that maybe he was the third son and the family was too poor to take care of him.

Maybe his mother was a teenager. In China it is very taboo to be unmarried and pregnant. My students told me a story that happened a couple of years ago about a college girl who got pregnant and the leaders of the school wouldn't give her the college diploma.

According to my students answers, I think the three main reasons mothers give up babies in China are:

1. too poor to afford another mouth to feed
2. teenage pregnancy
3. want to have a boy