Las Vegas is going back to its racy roots and downplaying family tourism, but the cruise industry is taking the opposite tack.

Many major cruise lines are chasing the family market, luring kids and parents with all-day children’s programs, kids-only swimming pools, pizza parties, teen discos and more.

For busy families with limited vacation time or for family reunions, cruises can appeal because everything — room, meals, entertainment — is organized by someone else and contained under one giant floating roof.

Work out what you and your kids want. Organized, all-day children’s programs or more independence? Lots of shipboard entertainment or more outdoors-oriented sights and shore excursions? A new megaship or a more classic or smaller vessel? (The new ships tend to have bigger kids’ areas, including special play rooms and pools.)

Study cruise brochures and Web sites. Among those with formal children’s programs are Carnival, Royal Caribbean, Norwegian, Princess, Holland America and, of course, the Disney Cruise Line, the most family-oriented of them all. Also work with a travel agent who books a lot of cruises; a good, experienced agent can steer you toward the right ship and may be able to get cabin upgrades.

If you plan to use a children’s program, double check that it’s guaranteed to be available on the dates of your cruise. Also ask about the children-to-staff ratio and the staff’s training, and the medical help that’s available on-board.

Some other basics:

• Comparison-shop for the rates on a third or fourth person in a cabin; sometimes there are very low fares. Some ships also have cabins that sleep five. But weigh the price against the greater space and privacy of adjoining cabins.
• Most youth programs are for children ages 3 to 17, although some cruise lines will take younger children. If you have a toddler, be clear on the toilet-training issue. On many cruise lines, the youth counselors won’t change diapers.
• If you plan to use a lot of baby-sitting for a younger child, check the hourly cost. It could be more economical and convenient to bring along another family member — a teenage niece or nephew — to provide baby-sitting.
• Ask about the availability of cribs (and make sure you cabin has room for one) and guardrails for bunk beds.
• Check on meal policies. Are there assigned times for dinner, or does the ship have the more relaxed, you choose-the-time-and-table restaurants? That’s much easier with young children.