https://policyexchange.org.uk/publication/a-portrait-of-modern-britain-youth/
'60% of 18–34-year-olds in the whole population sample
believed that if a child is questioning their gender, the child should be
offered counselling and support to help them understand why they feel
this way, with other interventions being deferred for a period, until it
can be seen whether the child persists in this belief or moves on from it
(sometimes known as the ‘watchful waiting’ approach), with only 24%
believing that the child should be affirmed in their belief and encouraged
to change their name and pronouns, to dress as the gender they wish to
be, and to take puberty blockers to prevent or delay puberty (sometimes
known as the ‘affirmative approach’).'
'There is some nuance to these responses, with young people more
receptive to trans ideology than the population as a whole. A plurality
of young people believe someone can be born in the wrong body and
divided opinions on whether biological males should have access to single
sex spaces. However, on other matters – including on competing in sports,
or on how children questioning their gender should be treated, young
people are sceptical of the view promoted by many trans rights campaign
groups, with views that align more strongly with those of gender critical
persuasion, who would support a watchful waiting approach for children,
that men cannot become pregnant, and that the women’s category in sport
should be reserved for biological women'
I've looked, but can't yet find, the source data. Will post if I do!