“I’m doing this for my son." Mum makes controversial plea in IVF groups.

An American mother has made an unusual request of parents with a known male embryo: she wants to trade it for her own female embryo.

Speaking to The New York Post this week, Lisa – the name she is referred to as to protect her privacy – explains that she and her husband are desperate for a baby son, because he would be a brother to their five-year-old child.

According to Lisa, a 37-year-old actor from Manhattan, a brother is something their son has been asking for, and the family are desperate to make that happen. So firm is their desire to have a boy, they are willing to perform an embryo swap with a family who would like their female embryo.

Technically, this would mean they would swap their biological daughter for a son not biologically related to them. Lisa suffered from infertility for nine years before she conceived her son, and the female embryo is the last one she has remaining after multiple rounds of IVF.

“I’m doing this for my son,” she tells The New York Post. “This is the way we want to complete our family.”

Lisa explains it’s something she has carefully considered with her husband, and something she wants for herself, even though she admits her son’s pressure about a brother has contributed to her decision.

“As soon as he could talk, he was asking for a sibling,” she says.

Finally, last week, Lisa decided to be more open about the situation. She posted in several IVF Facebook groups, seeking a swap of her female embryo. She wrote:

“Hello, we have been trying to give my child a sibling for three years . . . we want to complete our family with a son. We have a great quality female embryo. Would you like to consider a trade?”

Lisa's post was not received with empathy, with many members who are struggling to conceive even one child outraged by the perceived insensitivity of the request - resulting in the post being removed from one of the groups.

One woman, who has two male embryos after the conception of her son, contacted Lisa to discuss a swap. However, this transfer is not Lisa's preferred option, as she acknowledged it could become legally complicated as the embryo is in California.

Lisa won't give up hope, though, adding that she has an economical rationale to the request, too.

“We have a two-bedroom house with no space for a third bedroom. We bought it when Daniel was an infant, and now prices have risen so much in this neighbourhood. There is no way we could afford [a separate bedroom for a girl]. We’d have to move to Nebraska.”

And, after spending tens of thousands of dollars on IVF treatments over the years, Lisa feels that her female embryo is akin to an asset.

“Now I have a commodity — something I can leverage,” she says.

Lisa is unmoved by any criticism of her desire to surrender a biological potential child, for the sole reason of  gender preference. She firmly believes she's capable of loving, and raising, any child.

She did not address, however, how it may make her biological child feel to know she was swapped for a different gender. Rather, she sees it as a fair trade. (It is illegal to buy or sell embryos in the United States.)

Lisa is certainly a woman with a plan. She has even expressed a preference to implant a male embryo as soon as possible, so that she's pregnant by Christmas - so the age gap between her son and the new baby wouldn't be too great.

Furthermore, as her son is red-haired, she says that an embryo with similar features would be ideal.

In terms of what she has 'to offer', Lisa says the girl is likely to be blonde or red-haired due to her husband's Irish/British heritage.

She adds, “He also went to Yale."