How can one respond to friends who play with girls, and contend that they have not reached puberty, denying that touching a woman constitutes molestation, citing the saying of the Prophet, peace and blessings be upon him: "For one of you to be stabbed in the head with an iron needle is better for him than to touch a woman he is not permitted to touch"?

Children, even if they have not reached puberty, must be prevented from mixing in a way that leads to temptation (fitna). Guardians and teachers must prevent them from playing together in mixed groups. The questioner should advise them, and if they do not respond, their matter should be referred to those in authority over them to stop them. The aforementioned hadith is evidence for the prohibition of touching a non-mahram woman.