A group of parents in the United States has decided to raise their children in a gender-neutral way, allowing the children themselves to eventually self-identify as male or female.

The parents embarking on this bizarre new experiment in social engineering refer to their children as “theybies”—rather than “babies”—to underscore their gender amorphousness. They refuse to refer to their children as “he” or “she” and dress them in gender-neutral clothing and hairstyles, presumably to allow the children to drift toward a particular gender identity without parental prodding.

“A theyby is, I think, different things to different people,” theyby dad Nate Sharpe told NBC News in a report published last week. “For us, it means raising our kids with gender-neutral pronouns — so, ‘they,’ ‘them,’ ‘their,’ rather than assigning ‘he,’ ‘she,’ ‘him,’ ‘her’ from birth based on their anatomy.”

The parents of “theybies” do not reveal the biological sex of their children to anyone and try to educate their children into not associating their sexual body parts with being a boy or girl. “If no one knows a child’s sex, these parents theorize, the child can’t be pigeonholed into gender stereotypes,” NBC reports.

According to NBC, the gender-openness involved in the experiment also entails an explicit dimension of sexual orientation, noting that parents want to foster an environment “where the twins feel loved whether they grow up to identify as LGBTQ or not.”

Remarkably, “not everyone understands” the parents’ decision to keep the children’s sex private, NBC declares.

NBC further cited “experts” as saying that at birth, “reproductive organs reveal a baby’s assigned sex,” whereas gender “comes later, around age 4, when children begin to identify as masculine, feminine or somewhere along that spectrum.”

Dr. John Steever, assistant professor of pediatrics at the Mount Sinai Adolescent Health Center in New York, said that open-gender parenting could perhaps prevent gender dysphoria, “the distress a person feels when their gender does not align with their assigned sex at birth,” NBC reported.

Of course, “there is no research yet on how this type of parenting affects children,” NBC noted, which means that the children undergoing this social experiment will be the guinea pigs for the next generation.

Some experts like Steever, NBC adds, “say it’s unlikely that children would be confused by a gender-open upbringing,” although it is unclear upon what factors Mr. Steever is basing his professional judgment as an assistant professor of pediatrics.

Others, like Lise Eliot, professor of neuroscience at the Chicago Medical School and author of “Pink Brain, Blue Brain,” told NBC that eventually theybies will face a gendered world, which may be problematic.

“Once your child meets the outer world, which may be day care, or preschool, or grandparents — it’s pretty much impossible to maintain a gender-free state,” Eliot said. “And depending on how conventional your community is, you could be setting your child up for bullying or exclusion.”

One couple, who already refer to their second-grade daughter as “they,” has decided to raise their youngest child, 5-month-old Sparrow, as a “theyby,” calling the child both “pretty” and “handsome” to keep gender options open.

Sparrow’s father Dennis told NBC that he believes that “assigning your child a gender and giving them gender-coded lessons their whole life is much more coercive than what we do.”

It is unknown how many parents are currently rearing their children as “theybies” in the U.S., but NBC reports that a Facebook community for “theyby” parents claims some 220 members.

Follow Thomas D. Williams on Twitter Follow @tdwilliamsrome