Labia stretching: Why some British girls are told to do it
Young girls from some cultures are being forced to alter the appearance of their genitals by stretching their labia.
It is done in the belief that longer labia make sex better for men and stop them from cheating on their wives or leaving them.
But it's also a hidden form of child abuse, and the BBC has found evidence of it happening to girls in the UK, where forcing someone to do it is against the law.
This video contains graphic discussion of female genital mutilation.
If you need any help or support on FGM, you can contact the NSPCC's FGM helpline 0800 028 3550.