Renee Erickson, a Republican state senator from Wichita, Kansas, vowed to continue efforts to ban transgender athletes from participating in girls' and women's school sports.
"If not this year, we'll keep trying until we're successful," Erickson said.
Democratic Governor Laura Kelly vetoed the measure after labeling the bill "regressive." Kelly said the law would hurt the state's capacity to recruit businesses, but further emphasized that the bill signified a "devastating" message that "Kansas is not welcoming to all children and their families.
Kansas is one of more than 20 states that have considered a ban like this. The trend comes in response to an executive order by President Joe Biden aimed at preventing discrimination against transgender students.
"As Kansans, we should be focused on how to include all students in extracurricular activities rather than how to exclude those who may be different than us," Kelly's veto message said. "Kansas is an inclusive state and our laws should reflect our values."
For more reporting from the Associated Press, see below.

Idaho enacted such a ban last year, and Republican governors in Arkansas, Mississippi and Tennessee have signed measures this year.
Senator Roger Marshall, a Kansas Republican, has been vocal in supporting legislation in Congress. Supporters of such bans argue that that they ensure fair competition for "biological" girls and women and preserve decades of hard-won opportunities for them, including college athletic scholarships.
Supporters have also accused corporations and sports bodies such as the NCAA of trying to bully state lawmakers into not passing a ban.
"It doesn't exclude opportunities for biological girls and women, while her veto absolutely will," said Erickson, a former college basketball player who was the bill's leading sponsor.
Kelly's veto is likely to be an issue in her race for reelection in 2022. Both of her main GOP rivals, state Attorney General Derek Schmidt and former Governor Jeff Colyer, said earlier this week that they would have signed the measure.
"It's very important to our culture as a state," said Brittany Jones, advocacy director for the conservative Family Policy Alliance of Kansas. "But I also want to make sure that we're protecting girls now."
Supporters of the bill promised to try to override her veto. They'd have to persuade a handful of moderate Republicans who either voted against the bill or abstained. No Democrat voted for it.
Supporters needed to pick up only one more vote in the Senate but were eight short in the House.
Across the U.S., backers of such measures across the U.S. have pointed to the 15 championships won between 2017 and 2019 by two transgender high school runners in Connecticut, which prompted a federal lawsuit. They contend that "biological boys" have innate physical advantages in girls' and women's sports that would ruin competition.
Supporters of such bans generally have been unable to cite local examples of problems. The association overseeing extracurricular activities in Kansas K-12 schools said it has been notified of only five active transgender participants in extracurricular activities, and there is no known case of a transgender athlete having won a Kansas championship.
"The Legislature has picked up a nasty habit this year of sticking its nose where it doesn't belong and creating restrictive laws to address problems that don't exist," state Senate Minority Leader Dinah Sykes, a Kansas City-area Democrat, said in a statement after the veto.
Some critics worried that the measure, along with a companion proposal in Republican-controlled Missouri, could scuttle a bid by Kansas City to host 2026 World Cup soccer games. Also, the NCAA's Board of Governors earlier this month issued a statement in support of transgender athletes that raised the possibility that its championship games could be moved from states with such bans.
But LGBTQ rights advocates also argued that the measure attacked already vulnerable students and it would lead to additional bullying.
"This bill here is targeting kids as young as 5 years old," said Tom Witt, executive director of the LGBTQ-rights group Equality Kansas.
Freshman Democratic state Representative Stephanie Byers, of Wichita, the state's first elected transgender lawmaker, said that for trans youth, the veto "affirms who they are."
"It's about that mental health for those kids and seeing that they do have champions in the Statehouse," she said.