David Nuttall, MP for Bury North, asked the Home Secretary whether she agreed with him that extending the franchise to younger voters would mean they were more likely to be treated as adults, and therefore be at higher risk of exploitation.
Prompting gasps and sounds of incredulity from other Members in the house, Nuttall queried: "Does my Right Honourable Friend agree with me that if 16- and 17-year-olds are given the vote it increases the likelihood they will be regarded and treated as adults, and therefore increase the likelihood of them becoming victims of sexual exploitation?"
His remark earned the backbencher a diplomatic putdown from Theresa May, who rebutted him by saying she did not see any reason to link the two issues raised.
"I say to my Right Honourable Friend I would not link the issue of the age of voting with the issue of child sexual exploitation," she said firmly.
Nuttall's comment was also rubbished by Lib Dem leader Tim Farron.
"This is the most outrageous and ridiculous argument against Votes At Sixteen I have ever heard!" he lamented in a post on Twitter.
Nuttall is not the first MP to have raised the same issue in Parliament, though.
Back in June Labour's Barry Sheerman, a former chair of the education select committee, made similar remarks in a debate on who should be offered the chance to vote in Britain's upcoming EU referendum.
"Isn't what is missing out of this, is the responsibility we have to care for young people who are very vulnerable?" he asked fellow MPs.
"Up and down this country we've had vulnerability to sexual predators and ghastly things happening right though to 18, up and down this country."
He added: "This move to adults at 16 will make a lot of young men and women more vulnerable to sexual predation than happens at the moment."