A Democrat lawmaker has reminded Republicans trying to bring in an anti-trans bill that modern science recognises at least six different sexes.

James Talarico, a Harvard-educated former teacher, was speaking at a committee hearing about an anti-trans bill that will ban trans athletes from participating in sports at school in Texas.

Bill S29, the “Fair Sports for Women and Girls Act”, requires public school students to participate in athletic competitions based on their assigned gender at birth.

“The bill seems to think there are two [sexes],” Talarico said at a committee meeting on 20 April.

“The one thing I want us to all be aware of is that modern science obviously recognises that there are many more than two biological sexes,” he said. “In fact, there are six, which honestly… surprised me, too.”

Talarico went on to explain that there are “six really common biological sexes” based on X and Y chromosomes.

As well as the most common XX and XY set of chromosomes, Talarico reiterated there are also single X, XXY, XYY and XXXY sets of chromosomes, making a total of six sexes.

“The point is that biologically speaking, scientifically speaking, sex is a spectrum, and oftentimes can be very ambiguous,” Talarico said.

Beth Stelzer, the president of group Save Women’s Sports that is in favour of banning trans athletes from sports, said that sex is not a spectrum and that people with different chromosomes have a sex “disorder”.

“They are dimorphic: XX, XY,” Stelzer said of sex. “The other ‘sexes’ mentioned are disorders of sexual development that are variants of XX or XY chromosomes. They are still disorders of male or female.”

Examples from nature of animals with more than two sexes include a slime mold dubbed the “blob”, which has almost 720 different sexes. In 2011, a single-celled organism that lives in freshwater was found to have seven sexes. Another fungus, discovered in 2017, has more than 20,000 different sexes.

Other animals that don’t adhere to a strict sex binary include the hyena – all hyenas have a penis that becomes erect around female hyenas, who give birth through their penises (penises on females are larger than penises on males, too) – and lions, which have been observed changing gender in the wild.

Another anti-trans bill being considered is Texas State Bill 1646, is an anti-trans healthcare bill currently being debated in the state. The bill, which is supported by 13 Republican state senators, would consider a person guilty of child abuse if they “consent” or “assist” in providing a trans child with gender-affirming care.