Britain's schoolchildren will be taught about gay and trans-gender relationships as part of new compulsory government guidelines to be issued next week.
The new classes will be introduced across UK schools in 2020 following a six-month consultation period by the UK''s Department for Education, The Sunday Times reported.
The new statutory guidance will also spell out for the first time the end of parents' right to opt their children out of relationship and sex education (RSE) classes. The change will guarantee all children receive at least a term of lessons by the time they are 16.
Campaigners argue the lessons are required to protect children from child sexual exploitation online as well as to be taught about different types of relationships in society.
However, not all parents are on board with the concept and on Monday a petition signed by more than 100,000 people objecting to the new curriculum will be debated in the UK Parliament.
"We believe it is the parent's fundamental right to teach their child RSE [relationship and sex education] topics or to at least decide who teaches them and when and how they are taught. We want the right to opt our children out of RSE when it becomes mandatory in September 2020," the petition reads.
It notes grave concerns about the "physical, psychological and spiritual" implications of teaching children about certain sexual and relational concepts, which have no place within a mandatory school curriculum and would cause more harm than good.
UK education secretary Damian Hinds, however, has backed the need for the RSE lessons in schools as mandatory.
The country's education watchdog, the Office for Standards in Education, Children's Services and Skills (Ofsted), has also defended the need for such compulsory lessons.
"It's about making sure that children who do happen to realise that they themselves may not fit a conventional pattern know that they're not bad or ill," said Ofsted chief Amanda Spielman.
The debate followed a Birmingham teacher's own struggles to be able to use a set of five picture books to teach children about the varying forms of modern-day relationships.
"I'm just teaching children from an early age that there are different families out there and, let's not forget, that in some schools there are children with two mums, so I see it that they're not being taught anything. All they're seeing is their family is being accepted," said Andrew Moffat, the Assistant Headteacher who introduced the programme named "No Outsiders" at Parkfield Community School.
But parents, many from South Asian backgrounds, have been protesting against the lessons. They claim that it would confuse their very young children, aged between 4 and 12, and that it is too early to expose them to sexual issues.
Earlier this week, Moffat was named among the top 10 finalists of the annual £1-million Global Teacher Prize, to be awarded by UK-based Varkey Foundation in Dubai next month.
"His 'No Outsiders' programme teaches inclusiveness and diversity...Andrew now also uses 'No Outsiders' as a tool to reduce the potential for radicalisation," the Prize committee notes, adding that the programme's message of tolerance is a timely one.
Kulsuma Aktergetty images