SACRAMENTO, Calif. —Blended, multigenerational households, career-oriented grandmothers and energy to spare:
Just as they reinvented the teen years and the midlife crisis, the nation's 70 million baby boomers, born between 1946 and 1964, are reinventing grandparenthood.
Which is to say, boomers just don't feel like grannies and grandpappies.
"In the olden days, having grandchildren would initiate the sunset of people's lives," said Arthur Kornhaber, founder of Ojai, Calif.' s, Foundation for Grandparenting and a psychiatrist who has studied grandparenting since the 1970s.
"But the rules have changed, and there's an identity crisis."
For the 32 million baby boomers who are already grandparents, the approach to this stage of life is necessarily different.
For one thing, boomer grandparents are younger: The average age of first grandparenthood has dropped in recent years from 48 to 47, according to AARP. They're vital and active. They're likely still working. Their rockers are still rocking, and not on the front porch.
"Grandparents' role as living ancestor and family historian has been diminished," said Kornhaber. "For baby boomer grandparents, the crony role is big, being like kids together with their grandchildren."
Running around with the grandkids — hiking, swimming and playing sports with them — keeps boomers young. So does keeping current on their tech skills, so they can text the grandkids and be their Facebook friends.
While there are fewer grandchildren per grandparent than at any time in U.S. history, according to the Census Bureau, most grandchildren in this age of divorce, remarriage, single parenthood and other family complications have more than four grandparents.
Differentiating between the assorted grandparental parties is one reason for the wealth of nicknames — Nana, Lala, Mimi, Popsy and the like — that can make boomers sound more like Teletubbies than grandparents.
Because of a variety of factors, including economic hardships and the military deployment of parents overseas, 7.5 million grandchildren now live with their grandparents, U.S. Census figures show.
And, unlike most boomers' grannies, today's grandmothers have — or have already retired from — their own careers.
For baby boomers, the shift into the grandparent years involves changing the image of grandparents, says Allan Zullo, who wrote "A Boomer's Guide to Grandparenting" with his wife, Kathryn.
For many, it also involves a lot of responsibilities.
As Kornhaber says, being with young people can light up older adults' lives.