However, there are some ways to think about his "birthday":
* In-universe: His birthday might be mentioned in comics or other media within the X-Men universe. If it is, that would be the "official" birthday within the fictional world.
* Fan interpretation: Fans sometimes create their own headcanons about characters, including their birthdays. If a fan decides to give Cyclops a birthday, it's just a fan interpretation and not part of the official canon.
If you're looking for a specific date for Cyclops' birthday, you'll need to check comics and other Marvel media for any mentions of it.