The actor, who shares daughters Esmeralda, 6, and Amada, 4, with Ryan Gosling, started the conversation on Instagram.
"I'm often asked what my favorite red carpet dress is. This @versace is definitely up there," she wrote, alongside an image of herself wearing a gold fringe gown at a red-carpet event. "Im not often asked what my favorite parenting quote is, but I'll post it anyway."
Mendes then shared a quote that reads, "Spanking does for a child's development what hitting a spouse does for a marriage."
That sparked a robust conversation about discipline, punishment, and love among Mendes's fans.
One mama commented, "Love this quote! I have three kids so I understand the urge to spank! (Also most of us were raised in cultures or families where physical discipline is routine and accepted so I get it.)" She went on to say, "We have to model what we want to see in our kids. (And we won't be perfect so that includes apologizing when we mess up!)"
Another person said, "Thank you for using your platform to spread awareness about parenting ❤️ I wish i could do the same. So many children could benefit from it. Keep going beautiful momma! ❤️"
Many adults disagreed, arguing that spanking has a time, place and purpose in parenting.
"Love you but completely disagree," one woman wrote. "The goal in raising kids is not to have to spank, but it's correcting before they can reason behavior out with you. Completely different than hitting someone. That's not correcting behavior. We raised 5 respectful loving kind kids that were a joy to be around. Good fruit shows from loving correction."
"I don't know. I was spanked and now I'm a respectful adult. And believe me, I deserved those whoopings. I was a brat," wrote another.
Mendes replied directly to that woman, thanking her for her comment.
"So happy to agree to disagree," she answered. "Want this page to offer that in a loving way. We all parent our own way and I have no idea what I'm doing most the time. This didn't come with a manual so when there's something that resonates with me, I pass it on. Lotsa love ❤️"
Mendes also replied to another follower who wrote, "I don't understood how spanking is deemed acceptable for a child when it is frowned upon for adults. I'm so glad to be growing up at this time that this is being discussed more openly and challenged."
The Hitch actor replied, "So happy to be able to talk about alternative discipline now. When I was a kid that was not an option."
Mendes is absolutely right. When our generation was young, spanking was common. It was often the default form of discipline for many families.
As we grew up and became parents ourselves, we began to question whether spanking really has a place in modern parenting. From the conversation surrounding Mendes's post, many parents believe it still does. And many more are choosing alternative methods for disciplining their children.
The American Psychological Association has passed a resolution against spanking, arguing that it's harmful and doesn't work. Instead of spanking, the AAP suggests strategies like modeling appropriate behavior, explaining that there are consequences for breaking rules, and redirecting your child if they're misbehaving out of boredom.
You know your little one best, mama. But we know this: love, patience, and empathy can help any situation.