How can I respect someone’s beliefs when I think they’re wrong, ‘clutter’ or even repressive?
Our aim as professionals must be to provide a comprehensive Sex and Relationships Education. This means that we will work in such a way as to engage and educate all the young people in our group. To do this we may start from the observation of the Teacher who notes:
“In the class there may be people that haven't started puberty and people that are already sexually active, so it's quite difficult to cater for all the needs" 
So then, if our aim as professionals is to help young people to find ways to live sensibly and healthily, the question we need to ask is – ‘will this belief lead them to live unwisely or unhealthily?’ rather than whether we consider it to be the happiest or most reasonable way to live.
 “Religious moralities typically combine these shared human values with a good deal of clutter , and humanists will want to remove the clutter” p118 On Humanism . Richard J. Norman. Routledge, London, 2004
Though note Lila Green’s article on this and other Muslim views at http://www.independent.co.uk/news/education/schools/keep-the-faith-should-muslim-children-receive-sex-education-1756750.html