Chelsea Clintonis all about her growing family.

The newest addition to Clinton’s author résumé is a kids’ picture book that informs readers about 12 endangered species and how they can help save them.

And while Clinton, 39, was thrilled to share the news of her pregnancy with her parents, formerPresident Bill Clintonand former presidential candidateHillary Clinton, the real focus was her kids, she said.

“Admittedly, the most important audience — and this is nothing against my parents or Marc’s mom — but our most important audience is now our kids,” the vice chair of theClinton Foundationshared with PEOPLE.

Paul Archuleta/Getty

Celebrities Visit Hallmark’s “Home & Family”

Chelsea Clinton.Splash News Online

EXCLUSIVE: Pregnant Chelsea Clinton Shows Her Baby Bump While All Smiling Leaving The View In New York City

Source: Chelsea Clinton/Twitter

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“We were thrilled to share the news with my parents and my mother-in-law. They were so excited for us,” Clinton explained of her pregnancy.

Acknowledging that “every grandchild is so special,” she said it’s a “different dynamic” for her parents compared to her mother-in-law, former Congresswoman Marjorie Margolies. The next Clinton Mezvinsky will be the Clintons’ third grandchild, while he or she will be Margolies’ 23rd.

Chelsea Clinton during a reading at the Bronx Zoo.Julie Larsen Maher ©WCS

Chelsea Clinton Book Signing Event_BZ_04 02 19Credit: Julie Larsen Maher ©WCS

“Charlotte isso excited to be a big sisteragain,” Clinton told PEOPLE. “And I think Aidan is mainly excited because his sister is excited. He just loves and looks up to his big sister so much.”

Chelsea Clinton’s new book cover.Philomel Books

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Back in 2015, shortly after giving birth for the first time, Clinton revealed to PEOPLE that becoming a mother changed her entire world.

“I didn’t know I could care more intensely aboutanything until I became a mom,” she explained. “Somehow I love my husband even more, I love my parents even more. I feel even greater urgency about the work that I do, particularly around women and girls, being a mom of a daughter.”

“And I think my love for Charlotte has just opened more space in my heart and my brain that I didn’t even know was there,” Clinton shared.

Don’t Let Them Disappear: 12 Endangered Species Across the Globeis on sale now atamazon.com.

source: people.com