Parents have taken the Welsh government to court to stop gender identity and sex being taught to children aged three to 11 in primary schools.
Campaigners against the new Relationships and Sexuality Education curriculum, which is due to begin next week, are seeking a High Court injunction to prevent the policy.
They want a temporary ban until a judicial review to the curriculum is heard later this year, or an opt-out for parents to remove their children from the mandatory classes.
The legal challenge has been brought by Public Child Protection Wales who say the curriculum is inappropriate for primary age children.
Paul Diamond, representing the claimants, acknowledged the seeking of an injunction at the eleventh hour was an 'uphill task' but was 'one of those exceptional cases'.
