The Church of England's lead bishop on education has defended the government's new relationships and sex education lessons while stating that parents should have the right to withdraw their children. 

The Church of England was part of the government's consultation into the lessons, which will become mandatory across schools in 2020. 

Writing for Tes, the teachers' forum, Bishop Stephen Conway sought to allay the fears of some critics about the contents of the lessons. 

"It is pleasing to see a focus for primary school children on families of different types and healthy relationships, within the context of a set of shared values," he wrote.

"Primary aged children will not – as has been suggested – be expected to learn about intimate sexual relationships, which rightly comes at the secondary stage." 

He said that the Church of England had been "robust" in calling for the lessons to be "carefully targeted and age-appropriate" and for all schools, including those of a religious nature, to be able to teach about faith perspectives on the issues raised in the classes. 

"We have been robust where necessary, and we feel both that the consultation has been genuine, and that the government deserves to be congratulated for the finished product," said Bishop Conway, who is the Bishop of Ely. 

He said the focus of the guidance was not intimate sexual relationships but "promoting healthy resilient relationships set in the context of character and virtue development" and "respecting others, including the beliefs and practices of people with a specific faith commitment, as well as those from the many different types of families that make up our cultural context". 

He went on to express his desire to see all children participate. 

"The new guidance maintains the need for schools to consult their parental community in developing the curriculum, with parents ultimately having the right to excuse their children from sex education if they wish," he said.

"Our hope is that they will not do so, but this must nonetheless remain an option in order to honour legitimately-held positions of concern.

"While there should be no room for any form of discrimination, the mark of a genuinely plural society is respect for differing, sincerely-held views, whether about marriage or about other patterns of relationship which are societal norms today." 

The right of parents to withdraw their children has been one of the most contentious aspects of the new legislation, with parents of concerned that the content of the lessons will go against their beliefs.  

In Birmingham, hundreds of Muslim and Christian parents protested lessons at Parkfield Community School covering the Equality Act, including LGBT relationships.  The lessons were suspended after weeks of protests outside the school gates. 

The Coalition for Marriage has strongly criticised the new SRE guidelines, saying that they will "downgrade" marriage and "sideline" parents.

Under the new guidelines, sex education is not compulsory at primary school age.  In secondary school, parents have the right to withdraw their children from the classes until they are 15 unless the head teacher decides there are "exceptional circumstances" to grant their participation.  After the age of 15, the child can decide for themselves if they wish to take part in the lessons. 

Clarifying the opt-out rights, the government said: "There is no right to withdraw from Relationships Education at primary or secondary as we believe the contents of these subjects – such as family, friendship, safety (including online safety) – are important for all children to be taught."