Kelly, a Democrat in a Republican-majority state, also vetoed a bill aimed at making it easier for parents to challenge school materials they find objectionable, a type of legislation that has become popular among the far right this year.
The anti-transgender sports measure, Senate Bill 160, would have barred trans girls and women from participating alongside cisgender females in public schools, including state colleges and universities, and any private schools that compete against them. It would not have affected trans male athletes.
"We all want a fair and safe place for our kids to play and compete," Kelly wrote in a veto message Friday, The Topeka Capital-Journal reports. "However, this bill didn't come from the experts at our schools, our athletes, or the Kansas State High School Activities Association. It came from politicians trying to score political points."
She further cited the possibility of boycotts by businesses and the National Collegiate Athletic Association. "It would send a signal to prospective companies that Kansas is more focused on unnecessary and divisive legislation than strategic, pro-growth lawmaking," she said.
Senate President Ty Masterson, a Republican, pledged to try to override Kelly's veto when the legislature reconvenes next week, but when lawmakers passed the bill, they didn't have the two-thirds majority necessary for an override. An attempt at overriding the veto failed last year as well.
The so-called Parents' Bill of Rights, Senate Bill 58, likewise failed to attract a veto-proof majority. It would have required school boards to adopt policies providing for parental review of materials and processes for parents to seek removal.
Masterson accused Kelly of "choosing secrecy over transparency" by vetoing the bill, the Associated Press reports. But opponents of the bill said they're not hiding anything and that teachers regularly make lesson plans available to parents.
The Senate bill focused on curriculum dealing with race, although parents would have a right to object to anything. A similar bill in the House focused on sexual content. An early version of the House bill cited "homosexuality" as "harmful to minors," but the language was amended to make it more general. In any case, the House bill has failed to advance beyond the committee stage. Florida's more specific -- and infamous -- "don't say gay" law was touted as a "parents' rights" measure too.
Other governors who have vetoed anti-trans sports legislation this year and last include Democrats John Bel Edwards of Louisiana and Andy Beshear of Kentucky, and Republicans Doug Burgum of North Dakota, Spencer Cox of Utah, and Eric Holcomb of Indiana. Legislators have recently overridden Beshear's and Cox's vetoes. Such bills have also become law in Alabama, Arizona, Arkansas, Florida, Idaho, Iowa, Mississippi, Montana, Oklahoma, South Dakota, Tennessee, Texas, and West Virginia. The Idaho and West Virginia laws are temporarily blocked from enforcement while lawsuits against them are heard.