Ian Blackford called on Boris Johnson to withdraw legal challenge over two Bills passed unanimously by the Scottish Parliament.
Children’s minister Maree Todd said the Bill would make Scotland a ‘world leader in children’s rights’.
The institution denied the request to digitise leaflets detailing law firm internship opportunities.
MSPs dismissed the bill blaming lack of clarity over the total cost of such a scheme.
Sports teams, pride event organisers, national organisations and local support groups are among those to put their name to the paper.
The new legal right is known as Jack's Law, in memory of 23-month old Jack Herd who drowned in a pond in 2010.