Purity balls... no, it's not one of Christian Grey's gadgets in 50 Shades of Grey. The opposite, in fact - it's a special ceremony where a girl pledges to remain 'pure' until her wedding day. In doing so, she 'gifts her virginity' to her father until marriage (luckily, ours prefer socks or a Top Gear box set).
These balls originated in the US (where else?) and can now be found in 17 countries. They bear a slightly squicky resemblance to wedding ceremonies, with the girls - who are all around the age of 12 but can be as young as seven - usually wearing white gowns for the event.
To add an extra 'ick' factor, official guidelines advise that the ceremony take place when the girls are 'just old enough to have started menstruating'. If there's anything more embarrassing that your dad knowing about your period, it's then having to take a virginity pledge in front of him...
According to the ceremony, purity means the daughter will have no sexual contact of any kind until after marriage. And dating and kissing aren't allowed until they are ready for marriage, which we imagine leads to a wedding night with all kinds of surprises.
One of the largest purity balls in the US has been held for 14 consecutive years at the Broadmoor Hotel (no known relation to the mental hospital) in Colorado Springs.
A criticised for promoting the notion that the daughter is a possession to be protected by her father until she is 'given' to her husband.
Some ceremonies even involve the daughter being given a bracelet with a heart-shaped lock, to which her father holds the key until her wedding day, when he hands it over to her husband.