Emmy-winning journalist Lesley Stahl of “60 Minutes” has covered a lot of stories, but none perhaps as personal as the focus of her recent book, Becoming Grandma.

The book explores what happens when a woman becomes a grandmother -- and it’s profound. Based on her research, a biochemical transformation occurs. “We are literally transformed chemically when we hold or even have a grandchild,” she says.

When it comes to her own experience with her sweet granddaughters Chloe and Jordan, she tells Rach, “First of all, there’s nothing like the feeling that a grandmother gets when she picks up her baby’s baby. And it’s visceral.”

WATCH: Kelly Clarkson on Marriage, Motherhood + Her First Soul Album

She says that with her granddaughters living across the country, she “misses them physically,” and says the love she feels for them is new and different, calling it “unfettered.”

She explains, “When you have a child, you are responsible for bringing them up into good citizens -- having table manners, getting them to school, getting them to do their homework. There’s none of that with grandchildren.”

She loves being able to just say “yes, yes, yes, yes” to everything her granddaughters ask, saying it makes her feel good. “You like yourself so much for being like that, rather than the scold that you were with your own kids,” she says.

SEE: Dame Julie Andrews Embarks on an All-New Adventure + It Involves PUPPETS

Watch the video above to see what sure looks like a biochemical transformation to us -- Lesley lights up when she talks about Chloe and Jordan!