A California woman had to fight for the custody of her own biological son because she became pregnant with twins while she was being a surrogate for a Chinese couple.

After the babies were born, the surrogate mother Jessica Allen and her husband Wardell Jasper had to fight to get their own son as the Chinese family were his legal parents.

She described her experience to New York Post saying that the Chinese couple's frozen male embryo was inserted into her uterus in April 2016.

Reportedly, Jessica and Jasper waited to have sex until a doctor gave them permission, and said that they used condoms while doing so.

But, later when she went to the hospital, she discovered that she was pregnant with twins. Initially, it was assumed that both babies were of the Chinese couple.

Jessica revealed: "Not once during the pregnancy did any of the medical staff provided by the agency say that the babies were in separate sacs."

She added: "As far as we were concerned, the transferred embryo had split in two and the twins were identical."

They were however not identical. It happened through a rare medical incident called superfetation. Jessica was naturally pregnant with her own son as well as the child of the Chinese couple.

When the babies were born, they were immediately taken away from her in December 2016. Jessica did not even realise that the babies were different.

However, the couple later sent her a message saying: "They are not the same, right? Have you thought about why they are different?"

A DNA test was then done which revealed that one of the babies was of the Chinese couple but the other belonged to Jessica and Wardell.

A few days later, San Diego-based agency Omega Family Global said that someone from the agency was looking after her child, named Max because the Chinese couple wanted nothing to do with him.

Omega contacted Jessica to say that the couple expected between $18,000 and $22,000 as a compensation. If that doesn't work, the couple was thinking of putting Max up for adoption as they were still his legal parents.

However, it ended with a judge ruling that the family did not owe the agency or the Chinese couple any money for them to bring the baby, whom they renamed Malachi.

She added: "Wardell and I treasure Malachi with all our hearts. I don't regret becoming a surrogate mom because that would mean regretting my son. I just hope other women considering surrogacy can learn from my story."