During a 27-hour debate on House Republicans' health care plan in the House Energy and Commerce Committee, Shimkus suggested men could be opposed to former President Barack Obama's signature health care law because under the law they are required to pay for prenatal care.
"What mandate in the Obamacare bill does he take issue with? Certainly not with pre-existing conditions, or caps on benefits, or letting your child stay on the policy until they're 26," Democratic Rep. Michael Doyle said. "So I'm curious what are we mandating?"
"What about men having to purchase prenatal care?" Shimkus asked.
"There's no such thing as a-la-carte insurance, John," Doyle responded, a reference to the fact that most group insurance policies cover a wide variety of ailments and conditions that only affect men or women.
"That's the point. We want the consumer to be able to go to the insurance market, and be able to negotiate on a plan," Shimkus said.
Under Obamacare, insurers were required to cover maternity care as part of a package of 10 so-called essential health benefits. Prior to the law, it was difficult and costly to find maternity coverage on the individual market.
Republicans want to jettison this provision to give consumers a wider array coverage options. However, that change was not included in the health care bill Republicans unveiled Monday because it can't be passed through budget reconciliation.
The abortion rights organization NARAL called attention Shimkus' comments on Twitter.
"WOW. The #GOP's reason to object to insurance covering prenatal care? "Why should men pay for it?" Watch," the group wrote on Twitter, with a video of the exchange.
Shimkus' office did not respond CNN's request for comment.
Twitter users reacted to the NARAL Tweet to point to it as an example of sexism based on the apparent assumption that only women should pay for prenatal care.
"@NARAL Not saying we shouldn't but it's sexist for position GOPers to have, that men shouldn't be responsible for condition they help create," Twitter user BeccaM wrote in response to the Tweet.
She added, "@NARAL Women 'pay a little bit more' for every time a man seeks help with impotence or erectile dysfunction. Why should we pay for this?"
The House Energy and Commerce and the Ways and Means committees both held mark-ups on the House GOP's health care plan.
The GOP legislation would get rid of Obamacare's individual mandate and put in place refundable tax credits for individuals to purchase health insurance. It also proposes restructuring Medicaid and defunding Planned Parenthood.
However, the bill would preserve some of the more popular elements of Obamacare, including protections for people with pre-existing conditions and letting children stay on their parents' insurance plans until the age of 26.