Parents and kids today dress alike, listen to the same music, and are friends. Is this a good thing? Sometimes, when Mr. Ballmer and his 16-year-old daughter, Elizabeth, listen to rock music together and talk about interests both enjoy, such as pop culture, he remembers his more distant relationship with his parents when he was a teenager.

    “I would never have said to my mom, 'Hey, the new Weezer album is really great. How do you like it?''' says Ballmer. “There was just a complete gap in taste.”

    Music was not the only gulf. From clothing and hairstyles to activities and expectations, earlier generations of parents and children often appeared to move in separate orbits.

    Today, the generation gap has not disappeared, but it is getting narrow in many families. Conversations on subjects such as sex and drugs would not have taken place a generation ago. Now they are comfortable and common. And parent-child activities, from shopping to sports, involve a feeling of trust and friendship that can continue into adulthood.

    No wonder greeting cards today carry the message, “To my mother, my best friend.”

    But family experts warn that the new equality can also result in less respect for parents. “There's still a lot of strictness and authority on the part of parents out there, but there is a change happening,” says Kerrie, a psychology professor at Lebanon Valley College. “In the middle of that change, there is a lot of confusion among parents.”

    Family researchers offer a variety of reasons for these evolving roles and attitudes. They see the 1960s as a turning point. Great cultural changes led to more open communication and a more democratic process that encourages everyone to have a say.

    “My parents were on the 'before' side of that change, but today's parents, the 40-year-olds, were on the 'after' side,” explains Mr. Ballmer, “It's not something easily accomplished by parents these days, because life is more difficult to understand or deal with, but sharing interests does make it more fun to be a parent now.”