A teacher told students not to speak to their 13-year-old classmate because his father was a Conservative MP, the Commons has heard.
Bob Stewart said his teenage boy had suffered the abuse during the last General Election - and his three other children had also been "hassled" at school because of his political persuasion.
During a debate about abuse faced by prospective MPs in the run-up to June's vote, he said: "There's little that can be done about that because they're children, and my kids are robust enough to withstand it."
Mr Stewart's story was described as "deeply upsetting and deeply troubling" by Home Office minister Sarah Newton, who said the teacher involved had "let themselves down and let their profession down".
During the debate, Labour MP Graham Jones revealed that his eight-year-old daughter had been the target of abusive comments online, and the perpetrators had "disgracefully" called themselves Labour members.
He said: "We have families. It's about time that some people woke up to the fact that we're not robots.
"We're not there to be abused and there are other people who are victims of this who are not on the ballot paper."
Vicky Ford, the Tory MP for Chelmsford, told the Commons that a partially sighted candidate had been threatened with rape - and was subjected to online abuse from someone who wanted to "shoot her then pull the teeth out of her jaw while she fades away".
She also described how two Asian activists working for a Conservative candidate in Ealing were "spat at, told they should have their throats slit (and) were threatened that they should die".
Ms Ford called for better guidelines to be introduced on how the police should react to such abuse in the future.
Cabinet Office minister Chris Skidmore told MPs the Government would wait for a review by the Committee on Standards in Public Life before taking action.
The review is due to report back before the end of the year.