“Grey’s Anatomy” actress Caterina Scorsone shares details of her close relationship with her three daughters for People‘s cover story this week.

She opens up about what she’s learned since becoming mom to Eliza, 8, Pippa, who turns 4 next month, and Lucky, 10 months.

Reflecting on raising Pippa, who was born with Down syndrome, Scorsone says she was fearful at first, but expectations quickly went out the window and her “difference lit a match in my life and in the life of my family.”

“When my daughter Pippa was born, I was scared. I didn’t know anything about trisomy 21, the name for the occurrence of a third copy of the 21st chromosome, better known as Down syndrome,” she reveals. “I didn’t know anything. All I knew about Down syndrome was that people were afraid of it, so I figured I should be too.”

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The 39-year-old says that assuming how her daughter’s life was going to unfold was unfair. “It suddenly became crystal clear,” she explains, adding, “There is no standard, objective, perfect human being. The metrics of perfection are arbitrary and imposed in the service of those who fit them. My daughter is perfect. Exactly the way she is.”

“Pippa is perfect exactly as she is. So are you, and so am I. The only way we lose sight of that perfection is to look for it somewhere else,” she says.

Earlier this month, Scorsone, who shares her three children with ex husband Rob Giles, told “Good Morning America” all about how having Pippa forced her to redefine love, life and relationships.

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“I didn’t really know what family could feel like until I entered the disability community and met other families that loved and included a person with Down syndrome,” she reveals. “These hilarious, real humans reached their arms around us when Pippa was born and pulled us into the most joyful, fierce hug we’ve ever experienced.”

She explains how her daughter’s “authenticity” shines through in the way she communicates: “This gift of honouring her authentic moment, as a woman and as a mother, we can all learn from it.”

Speaking about how she now has a a new perspective on parenting, Scorsone says “the birth of a baby with Down syndrome is something to be celebrated rather than feared.”