The Birthday Problem

Within a group of 22 people, you have a 50% chance of finding two people with the same birthday.

This doesn’t make sense normally because there are 365 days in the year, therefore it should be a 22/365 chance of finding someone with the same birthday as you within a group of 22. But my Genetics professor proved it in class. Twice he asked a group of 30-40 students (different group each time) to start stating their birthdays. Both times he found found two students with the same birthday before he even got past the six month.

I guess babies like being born on certain birthdates?
…Or parents like babymaking on certain days.