Do I need a passport for a cruise?

    One is recommended because if the need to return from a cruise port of call, a passport is required to board a flight.

    Why are airlines asking for full names, date of birth and gender?

    It is required by TSA for the secure flight program.
    Secure Flight Program

    What can I take on a flight and what does 3-1-1 stand for?

    Liquid and gels that are less than 3.4oz, put in a quart size bag. For detailed information what can and can not be taken on a flight, click on this link:
    TSA 3-1-1