Chelsea Clinton: Charlotte not sure what sibling means yet

NEW YORK, NY - OCTOBER 19:  Marc Mezvinsky and Chelsea Clinton attend The Headstrong Project's 3rd annual Words of War event at One World Trade Center on October 19, 2015 in New York City.  (Photo by Cindy Ord/Getty Images for The Headstrong Project)

(CNN)Chelsea Clinton, who is expecting her second child this summer, is having a hard time convincing her 15-month-old daughter Charlotte that a sibling is on the way.

"She says 'baby,' and then points to herself!" Clinton joked.
As reported by People magazine, Clinton spoke to an audience at the American Library Association Conference in Boston on Monday about her experience as a new mom, and her own famous mom's bid for the White House.
"I don't think [Charlotte] has any idea what that means yet, but we're talking about it a lot," Clinton said about her attempts to talk to her daughter about the newest member of the Clinton family.
And since she was addressing to the American Library Association Conference, Clinton talked about her family's love of reading and her efforts to pass that legacy on to her daughter.
"We have deep conversations about 'Click, Clack, Moo,'" Clinton joked about the children's book, adding that she enjoys reading with Charlotte curled up in her lap.
Clinton was also asked about a different family legacy -- her own potential political career. "I always answer the question the same way. I absolutely understand why you're asking me that question," Clinton deflected. "My last name is Clinton. My dad was president. My mom's running for president."
"But you should be asking yourself this question," Clinton said. "That's a question every one of us should be asking ourselves."