Madonna has banned her daughter from dating until she is 18.
The singer got worried when ten-year-old Lourdes attracted a lot of attention at the premiere of new animated film 'Arthur and the Invisibles' - in which Madonna voices a character - and has warned her to stay away from men until she is an adult.
A source told the National Enquirer magazine: "It must come from her strict Catholic upbringing.
"Everyone told Lourdes how gorgeous she is at the 'Arthur and the Invisibles' premiere, which sent a red alert to Madonna!
"It made her nervous to think that in just a few years guys would be hitting on her only girl."
Madonna has previously admitted to being a strict parent.
The 48-year-old singer has banned Lourdes and her younger brother Rocco from watching TV and eating junk food, makes them earn their treats, and if they leave clothes on the floor they end up in the trash.
Madonna - who is married to British film director Guy Ritchie - said: "My kids don't watch TV. We have televisions but they're not hooked up to anything but movies. TV is trash. I was raised without it. We don't have magazines or newspapers in the house either.
"My daughter has a problem picking things up in her room. So if you leave your clothes on the floor, we put them in a trash bag. She has to earn them back by being tidy. I'm a disciplinarian. Guy's the spoiler."