Facebook : Which example applies to you?

If you are Facebook user, you would have come across message like this. Which example applies to you? in regards to your gender like

Which example applies to you?
Right now your profile may be confusing. Please choose how we should refer to you.

yourname edited her profile.
yourname edited his profile.

Do you know why do you get this annoyed message ? It is facebook’s security check to protect you. Sometimes this goes away if you close the window.