LGBT History Month has taken place every February since 2005. It was conceived by 'gay rights' campaigners with the aim of educating pupils to recognise homosexuality as normal.
In the past it has tried to teach children that Florence Nightingale was a lesbian and that Isaac Newton was gay.
The organisers commend the efforts of one school in Stoke Newington in 2007. In a report on the school's events, the teacher responsible said: 'Six girls tried to walk out of the Year 9 assembly because they were Christians and their parents had said they were not to take part in any of the LGBT celebrations.'
The teacher said the girls were told 'students must not be racist, sexist or homophobic' and were made to attend the assembly despite their beliefs.
Its current suggested lesson plans include discussing genes, gender and the concept of 'intersex' in science, producing images of LGBT people in art, and exposing Leonardo Da Vinci's bisexuality in Design and Technology classes.
Since the repeal of Section 28 of the Local Government Act in 2003 there has been no statutory ban on the promotion of homosexuality in schools.
LGBT History is sponsored by several Government departments, police forces and other public bodies.
Women and equalities minister Harriet Harman, and MEP Michael Cashman, will also be present at the Downing Street reception.
Organiser Tony Fenwick said: 'This is a fantastic moment for the LGBT community; we really are on the threshold of something big.
'Who would have thought five years ago that a group wanting to put lesbians, gays, bisexuals and trans people into the National Curriculum would be welcomed by the Prime Minister of our nation?'
The organisers of LGBT History Month say: 'Schools have a crucial role in educating for equality. They have a responsibility to every pupil to ensure a safe and secure learning environment in which they can thrive. They have a responsibility to all pupils to prepare them for adult life in the real world.
'A key part of of the educational process is to ensure that the culture of our schools is inclusive and welcoming. Countering the prevalent assumption that everyone represented in the curriculum (including the hidden curriculum) is heterosexual becomes essential.'
They say: 'This focused month is uniquely placed as a national initiative encouraging staff and students alike to collectively challenge the homophobia and prejudice which is endemic in our society.
'Diverse images round the school that include LGBT people at work and as parents contribute much to set new norms.'
The organisers offer the following examples of how another school incorporated LGBT History Month into the curriculum.
* Maths lesson explored the work of Alan Turing, [a gay man], known as the Father of Computers.
* English lesson read James Baldwin [a gay man], and explored how his sexual orientation affected his work. Jackie Kay, a lesbian of black Scottish heritage is another fine writer pupils can study.
* Geography lesson explored population movement and discovered why and how LGBT people move to cities around the country and sometimes move to new countries.
* Religion class explored how various texts mention sexual orientation and gender and how people differ in their interpretation and behaviour and how these can be interpreted in terms of social harmony.
* Media lessons explored the images of LGBT people and why they are predominately young and male and white people.
* Science lesson discussed genes and gender and the concept of intersex.
* Art class used to produce images of LGBT people that could be used in the school
* Drama season used LGBT History as the basis of an improvised play to educate and entertain the whole school on the issues.
* Design and Technology lesson on some of Leonardo da Vinci's inventions, and remembering to expose his bi-sexual identity.