It's almost instinctual: You hold your baby, adorable in her footed pj's, and you have the irresistible urge to toss her up in the air, see her face light up, and catch her safely in your arms. But are baby rides and roughhousing safe?

Not if your baby doesn't have head control; even light tossing could cause strain on her neck, says Heather Armstrong, M.D., a pediatrician in Lighthouse Point, Florida. Head control usually develops by 4 months, but it's best to be extra careful with her until 6 months, when her neck muscles have really strengthened.

Even then, take it easy. Instead of tossing your tot in the air, you can lift her just above your head without taking your hands off her. Or try light knee-bouncing to avoid the risk of dropping the baby.

Swing safely. If you want to spin your older infant or toddler around, hold her under her arms, not by her hands or wrists. Pulling on a child's arms can dislocate her elbow (called "nursemaid's elbow") and cause pain. If your child cries and holds her arm after playing, see your doctor right away; she can maneuver the ligament back into place.

Be a tame tickle monster. Tickling is great fun, but "babies tire out from it very quickly," says Dr. Armstrong. So if she stops laughing, stop the tickling.