Jessica Allen was already the mother of two boys when she decided to become a surrogate.
The pay she would receive to carry another woman's child to term - $US30,000 - would allow Allen to become a stay-at-home mum, as well as save for a new house. It would also be her "chance to give a family the blessing of a child," her partner, Wardell Jasper, told her, according to the New York Post, which first reported the story.
So Allen signed up to become a surrogate with the San Diego-based Omega Family Global, which matched her with a Chinese couple identified in the article only as the "Lius," a pseudonym. In April 2016, after in vitro fertilisation treatments, Allen became pregnant with the couple's baby.
Six weeks later, the first of many surprises in her surrogacy would crop up: A second baby had appeared in her scans.
"I was a bit scared, but I heard the Lius were thrilled to be having twins," Allen, 31, told the newspaper. "My $US30,000 payment, including expenses - which I received in instalments by check each month - was increased by $US5000 for the second child. Not once during the pregnancy did any of the medical staff provided by the agency say that the babies were in separate sacs. As far as we were concerned, the transferred embryo had split in two and the twins were identical."
Last December, Allen gave birth to both babies by C-section at a hospital in Riverside, California. She claimed she was not allowed to see the newborns or spend an hour with them, as her contract with Omega Family Global had outlined - leaving her heartbroken days after the delivery. She had only briefly seen a cellphone picture of the babies and remarked that they looked different.
Only later would she realise how accurate her observation had been.
On January 10, nearly a month after the babies were born, Allen said she received a message from "Mrs. Liu" with another picture of the twins.
"They are not the same, right?" the message read, according to the New York Post. "Have you thought about why they are different?"
A DNA test would soon reveal the truth: One of the "twins" was actually Allen and Jasper's biological son. Despite using condoms, they had apparently conceived the child after becoming pregnant with the Lius' baby, in what is believed to be an extremely rare case of superfetation.
The condition - in which an already pregnant woman conceives another child - is so rare that alleged cases are usually treated with skepticism.
In a widely publicised 2009 case of a pregnant Arkansas woman becoming pregnant "again," Karen Boyle, a reproductive medicine specialist, told ABC News there were only about 10 reported cases of superfetation in medical literature.
"I was heartbroken knowing I carried a baby I didn't know was mine and that he was taken from me without my knowledge and was in the arms of other people where he did not belong," Allen told the Independent.
She and Jasper became focused on getting their son back, Allen added.
What followed was a lengthy, expensive legal battle. The San Diego agency reportedly told Allen that the Lius had relinquished the baby who was not their biological match - and also wanted up to $US22,000 in "compensation." Allen told the New York Post they couldn't afford that and were shocked when the agency put up other barriers to reuniting with their son:
"To my disgust, a caseworker from the agency lined up parents to adopt him and 'absorb' the money we owed the Lius. Or, if that didn't work out, the Lius were thinking of putting Max up for adoption, as they were still his legal parents.
"I told the agency in no uncertain terms, 'We want our son' but we would still be responsible for the bill if we kept him. It was like Max was a commodity and we were paying to adopt our own flesh and blood. A caseworker from the agency also said we owed her a further $US7000 for expenses she had incurred for the bureaucracy and for looking after our son.
"We spent $US3000 on an attorney, and there was a lot of strained negotiation between us, our lawyer and Omega. It was an uphill battle, but the agency finally reduced the 'fee' we owed the Lius to zero.
"Despite the monetary dispute being resolved, Omega Family Global, in a statement to the New York Post, disputed Allen's claims. The full letter from a lawyer for the agency is here."
In the United States, commercial surrogacy - carrying another woman's baby with monetary compensation beyond medical expenses - is legal only in a few states, including California, where Allen lives. The practice comes with a slew of ethical and legal questions, including what rights the surrogate mother and the child have, particularly when the surrogacy takes place in another country.
Although the Centers for Disease Control and Prevention publishes statistics on assisted reproductive technology, which includes "donor embryo services" and "gestational carrier services," the federal agency's data does not break out exactly how many of those births were by surrogacy. About 1.6 percent of all infants born in the United States each year are conceived using assisted reproductive technology, a figure that has doubled over the past decade, according to the CDC.
For Allen, her surrogacy was a "nightmare" that ultimately had a happy ending. She told the New York Post her family was reunited with her son on February 5, in the parking lot of a Starbucks in Riverside County. She and Jasper renamed their newest family member Malachi, and he is now 10 months old.
"The moment was incredibly emotional, and I started hugging and kissing my boy," Allen told the newspaper. "Wardell and I, who got married in April, weren't planning to expand our family so soon, but we treasure Malachi with all our hearts. I don't regret becoming a surrogate mum because that would mean regretting my son. I just hope other women considering surrogacy can learn from my story. And that a greater good will come out of this nightmare."