[header] How to hold a sleepover with boys and girls [title] Act responsibly for a few weeks before you ask. [step] Your parents are much more likely to agree with your sleepover plans if they feel that you're responsible enough to host a mixed-gender sleepover. Get them in the right frame of mind to agree by acting as responsibly as you can for a few weeks before you ask. 
Do your chores without being told, listen to what your parents say, and keep your grades up. [title] Mention your idea to your parents to see how they react.