Amy S. Foster On Her Feminist YA Trilogy & Why She's So Protective of Dad David Foster's Fiancée

As the #MeToo movement shakes up American society, Amy S. Foster, daughter of legendary producer David Foster, is taking a jab at sexism with her YA science fiction series, The Rift Uprising trilogy.

How? By redefining what it means to be strong and female. Her series features a teenage super soldier, Ryn Whittaker, who leads a rebellion and falls in love. Plus, Foster’s dad is a “huge fan.”

“It’s hard for girls to identify with warriors, but we are warriors. We fight all day long, all the time,” Foster, 45, tells PEOPLE in an exclusive interview about what she hopes readers will learn from the last book in her series, The Rift Coda, which hit stands earlier this month. “[By allowing women to be soldiers] you’re not lessening the standards, you’re just changing the fabric of the standards. I hope that we start to see ourselves as warriors.”

Foster — who is also known for her songwriting (she cowrote four hit songs with Michael Bublé) — released the first book in her series, The Rift Uprising, in 2016. The book follows Ryn as she and her fellow soldiers guard The Rift, a tear in the universe that leads to “alternate Earths.”

“I was like, ‘I’m going to write a book where, even though they’re super soldiers and they’re in these extraordinary circumstances, they talk and act like teenagers.'” Foster says. “They say ‘f—’ and talk about ‘f—ing,’ because that’s what teenagers do.”

By a creating complex and realistic protagonist, Foster hopes to challenge stereotypes in which female soldiers are “virgins” or “sterile” (like the Black Widow).

“[Female warriors] are constantly having to choose between love and power in a way that men don’t have to,” she explains. “So this set me on a journey of reinventing the trope of the female warrior. What does she bring to the table so she’s not just a guy with boobs? How is she different?”

Rivaling The Hunger Games in action and angsty romance, Foster’s latest book traces Ryn’s transformation from follower to leader — one tasked with ending an uprising that she started. And Foster’s dad, who has read the books and posted about them on Instagram, is “mega supportive.”

She jokes, “He was far more impressed [with the series] than with any song I’d ever written. Just way more impressed.”

For the rest of her wide-ranging interview, Foster puts the jokes (mostly) aside to discuss her place in the science fiction world, how she combats sexism while raising her three children, and why she’s been so publicly protective of her dad’s fiancée Katharine McPhee, who is 34 years younger than her soon-to-be husband.

How does your series push back on female stereotypes?

When the first reviews started to come out, I’d never gotten a bad review, but the readers were very confused. They’d be like: “Why is [Ryn] talking about love? Why is she talking about a boy? Is she doing all of this because she’s motivated by sex?”

Have you met a 17 year old? Yeah. She pretty much is… People were like, “No, the love story shouldn’t be important. She’s a fighter.” I was like, “Why can’t it be?” Buffy [in Buffy the Vampire Slayer] would kill vampires and then she’d think about Spike, she would think about Angel, she’d think about her clothes, and her friends. It didn’t make her any less tough. I don’t know how we’ve strayed from this, especially in this time. I don’t know how we’ve forgotten the fact that women should not have to choose between being a powerful, sometimes unapologetically violent, human beings and also want love in their lives.

What do you want readers to take away from the book?

It’s not really “down with the patriarchy,” it’s “down with hierarchy.” It’s down with this idea that someone leads from the top like a pyramid… What I would love for women to explore is this idea of a nonlinear leadership. It’s like a concentric circle rippling out. You listen to everybody at the table and everyone’s voices are equally valid. You can step up to someone and say, “I’m not so great at this, this person is better. But I can do that.”

Were you raised to embrace your power, or is that a lesson you learned later on?

I was born in the ’70s. I was three years old until [women were allowed] to get a credit card without a man’s signature. Am I going to say that didn’t play a factor in how I was raised? I think we’re just beginning to see how institutionalized sexism informs our choices as children and as parents.

I have three kids, two daughters and a boy. Sometimes my son, who is 8, likes to dress up like a girl. It’s fun to be a girl. You get to wear makeup and you get to wear [cute] clothes. Girls are allowed to play around with their masculinity and have short hair and wear pants and play baseball and soccer. But anytime a boy steps his toe into something feminine, he’s labeled queer or weird or different or gay or wrong… If we project that onto our sons then how can we get past sexism? When we’re telling them if they dress up like a girl there is something wrong with them. I don’t care what he is, but he sometimes thinks it’s fun to put makeup on and wear a dress. Why wouldn’t he, because it is?

How did your parents raise you?

My dad, he’s always been so supportive. He’s about to be married for the fifth time so he’s very romantic and traditional. But my father never said, nor did my mother ever say, “You can’t do that because you’re a girl.” No one ever really said that.

How do you feel about your dad’s upcoming wedding?

Thrilled. So happy… We are all 100 percent supportive of his relationship with Kat. She is not only super talented, but one of the most genuinely nice human beings. They’re great together. Everyone in the family is really happy.

RELATED VIDEO: Katharine McPhee and David Foster Open Up About Their Love: ‘It Doesn’t Make Sense to A Lot of People But It Does to Us’

You’ve been very public in your support of their relationship. Can you tell me why?

No one else needs to judge this relationship. I am amazed at why people believe that they have the right to judge, not just my dad’s relationship, but anyone else’s relationship… You don’t need to judge what you don’t understand. You’re not in it, you’re not living it. Specifically I was speaking to all of the really disgusting comments that I was seeing that were labeling her as some kind of gold digger. I was like, “Are you serious?” She’s so successful in her own right. She could have anyone.

By the way, “gold digger” is a gross term anyway. What does that even mean? That’s another thing that we need to reframe. If a woman is in a relationship or a man is in a relationship, and they’re bringing stability and love and respect and honor and partnership and the other person just happens to be wealthy — well okay. All of these things need reframing. Specifically to Kat, it just really bothered me as a feminist. Why are you dragging her and saying this?

How does that type of criticism speak to sexism at large?

On a deeper level it’s this idea of perception and what people, especially women, are entitled to. You can’t just be naturally beautiful and funny and amazing and great. [Trolls think,] “I’m going to take you down a notch because you can’t [be all of those things].” Why can’t you? Why do you need to be put in your place? I’m extra about my feminism.

How do you hope your books will help change women’s perceptions of themselves?

Don’t just dismiss [the books] because you think, “I can’t relate to a girl [like that].” Oh, can’t you? Haven’t you ever been that angry? Don’t you wish you had that much power? Don’t you wish that you could live everyday and not be afraid of anything?

The Rift Coda is on sale now.