At 75 years old, when Sarai saw that she was still unable to conceive, she decided to give her handmaid, Hagar, to Avram (Breisheet 16:2-3):
Sarai said to Avram: “See now, God has restrained me from having children; Come to my handmaid; perhaps (ulai) I will be built up through her”. Avram listened to the voice of Sarai. And Sarai, Avram’s wife took Hagar the Egyptian, her handmaid, after Avram had dwelt ten years in the Land of C’naan and gave her to Avram, her husband to be his wife.
Sarai was hoping that Hagar would serve as a surrogate mother for her child. The fact that she said ulai, perhaps, shows that she wasn’t sure how it would turn out.
When Sarai realized that her husband was already 85 years old, and she still had not been able to bear a child for him, while she herself had already reached the age of 75, she thought that she had no longer any hope of conceiving herself. She therefore reasoned to herself, that seeing God had promised Avram that he would have children of his own who would inherit the Land of Canaan, God must have referred to his siring children from another woman. She reasoned further that it would be in her own best interest that any children born to her husband should be born by a woman under her control so that she would experience the joy of motherhood at least vicariously.
All children are a building consisting of genetic input by father and mother. Sarai said that any son from this union with her husband would be accepted by her as if he were part of her biological family. She would treat him as her own son.
Sometimes surrogate motherhood worked in the Tanach and sometimes it didn’t.
In the case of Sarai and Hagar it did not work. Hagar’s son, Yishmael was never considered to be Sarai’s baby. In the end, after her name was changed, Sarah was blessed to have Yitzchak, a baby of her own, fifteen years later.
There are other cases where surrogacy did seem to work such as with Rachel and Leah’s handmaids, Bilha and Zilpa.
In Breisheet 30:3-6, Rachel gives her handmaid, Bilha to Yaakov and she is confident that Bilha will serve as a surrogate mother:
Rachel said (to Yaakov), “Here is my maid Bilha. Come to her and let her give birth on my lap. Through her I will then also have a son.” So she gave him her handmaid Bilha as a wife, and Ya’akov came to her. Bilha conceived and gave birth to Ya’akov’s son. Rachel said, “God has judged (dan) me and has also heard my prayer. He has finally given me a son.” Therefore she named the child Dan.
In Breisheet 30:7-8 we read:
Rachel’s maid Bilha conceived again and gave birth to a second son by Yaakov. Rachel said, “A fateful contest I waged with my sister; yes, and I have prevailed.” So she named him Naphtali.
In Breisheet 30:9-13 Leah took her handmaid to be a surrogate as well:
When Leah realized that she was no longer having children, she took her maid Zilpah and gave her to Jacob as a wife. When Leah’s maid Zilpah bore Jacob a son, Leah said, “What luck!” So she named him Gad. When Leah’s maid Zilpah bore Jacob a second son, Leah declared, “What fortune!” meaning, “Women will deem me fortunate.” So she named him Asher.
When Bilha and Zilpa gave birth, their sons were considered to be Rachel and Leah’s children. Rachel and Leah named the babies who became equal members of the Twelve Tribes of Israel.
We see from here that even in the days of the Torah, sometimes surrogacy worked and sometimes it didn’t.
One difference between then and now is that in the time of the Torah the surrogate mothers were handmaids and didn’t have a say in the matter while today a woman chooses to serve as a surrogate.
May all those who are seeking to have a child be blessed!