The 39-year-old is mum to Eliza, eight, Pippa, three, and 10-month-old Lucky, and, speaking to People, she explains having her second child "cracked open a door in my life".
"When my daughter Pippa was born, I was scared," admits the actress. "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."
"I didn't know anything," she explains, sharing that, "All I knew about Down syndrome was that people were afraid of it, so I figured I should be too."
However, Scorsone insists her perspective quickly shifted, as she began seeing Pippa's differences as signs of her individuality.
"It suddenly became crystal clear - there is no standard, objective, perfect human being," she reflects. "The metrics of perfection are arbitrary and imposed in the service of those who fit them."
She continues: "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."
Scorsone says her life has been infused with kindness ever since Pippa was born - and since she has connected with other families with special needs children.
According to Caterina, Pippa's arrival has really enhanced her life as she "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".
"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 smiles, adding, "the birth of a baby with Down syndrome is something to be celebrated rather than feared."