These ‘secret admirers’ are asking politicians including Jeremy Corbyn, Justine Greening and Iain Duncan Smith to back an amendment that would see all teens receive “age-appropriate”, religiously diverse and LGBT-inclusive lessons.
Under current government guidelines - which were last updated in 2000 - only state schools are required to teach students about the biology of sex, leaving thousands of children at academies, private schools and free schools in the dark.
It is also not mandatory for any institution to give lessons about the social and emotional aspects of relationships, such as consent, or to offer LGBT sex and relationships education (SRE).
Parliament are due to vote on the amendment to the Children and Social Work bill later this month.
As part of the joint project by National Student Pride, sexual health charity the Terrence Higgins Trust and the NUS LGBT+ campaign, more than 400 students have written to their MP to explain what supporting the change would mean for young people.
Angie Normandale, a 23-year-old student, said her the SRE at her school was “scaremongering”.
“It had no relationships, no consent, no gender and no pleasure,” she said. “My poor SRE contributed to body shaming and poor mental health.
“Thanks to Privilege and the Queer Youth Network, I received a lot of extra help, but prevention is worth more than cure.”
Bethany Glover, a student at the University of Westminster, said her lack of knowledge - and that of her classmates - made it more difficult for her to come out.
“I realised I hadn’t been prepared about how to talk being bi. We’d been taught about ‘normal sex’,” the 19-year-old said.
“People reacted to my sexuality thinking it was how they had seen on the internet. I know I would have been more confident if I was told being bi was normal.”
Alex Phillips, campaigns officer at the Terrence Higgins Trust, said failing to teach LGBT sex education was putting young people’s health at risk.
“By excluding them, they may turn off and not think condoms are relevant for them and then not have great sexual health,” she explained.
“From an emotional point of view, it can be very detrimental to their mental health if they are sitting in a classroom and the focus is on heteronormative relationships.
“They are going to think that the feelings they have are not valid or normal and that is very damaging.”
Jamie Wareham, communications director at National Student Pride, added: “The tradition of sending anonymous Valentine’s cards seems to have disappeared over time, but today, hundreds of MPs across the country will be opening their doors to piles of cards. And unlike most, these Valentine’s cards actually mean something.
“This month, MPs have a once-in-a-generation opportunity to make SRE mandatory in every school in the country.
“If these cards can persuade MPs to vote for mandatory SRE to be included in the Children and Social Work Bill, this could transform the experiences of young people everywhere, as they grow up and navigate their own sexuality.”
Sex and relationships education is also set to the be theme of National Student Pride’s annual event.
For more information about the weekend, 24-26 February, visit studentpride.co.uk