With one simple purchase, a Michigan mom learned how important it is to let kids truly be themselves.

On June 22, Erin Farias wrote on Facebook that her 3-year-old son, Hendrick, asked for glasses with purple frames when he outgrew his dark blue glasses. The mom of three from Grand Rapids, Michigan, wrote that she was nervous that other kids would make fun of him and bought green glasses for him instead.

"I didn't want him to be teased. And I kept pointing to the green ones asking, 'Don't you like the green ones?'" she wrote. "And here I was, the mom who passionately wants her sons to be who they are -- telling my son which glasses he should love."

When those glasses became scratched up, Farias decided to buy her son the purple frames. When he put them on, she realized how much having glasses in his favorite color meant to him.

"When his new purple glasses arrived and I presented them to my sweet boy ... he squealed with the purest joy," she wrote. "His smile radiated confidence."

Farias told The Huffington Post that Hendrick's twin brother, Andres, requested pink frames after seeing his sibling's glasses. Knowing Andres doesn't need glasses, his mom ordered just the frames for him. Andres also prefers using pink cups and plates and adores his Barbie who has a pink kayak. At first, Farias presented other options to her sons when they picked out toys. She now regrets ever trying to change her kids' minds.

"In the past, every time my boys have chosen the item more geared towards girls, I would present a similar item, 'Don't you like this one better?'" she told HuffPost. "And I now feel guilty that I used to do that -- that I would allow the gender stereotypes of society to pressure me into molding my boys to fit these narrow definitions, rather than allowing my boys to define themselves as who they wanted to be."

Erin Farias Erin Farias' 3-year-old son, Andres, adores his pink bike.

While potty training her sons, Farias decided to let her sons pick out the underwear they wanted as a reward. Hendrick wanted Queen Elsa from "Frozen" on his, and Andres wanted characters from "Minions" that happened to be pink. Even though the patterns didn't come in boys' options, Farias bought them anyway.

"My boys rock panties and that's just how it is," she told HuffPost. "But perhaps someone, someday, might make some underwear with Elsa on them or in pink that may be a little more comfortable for my boys."

Farias said she still worries about kids teasing her sons and has received criticism from adults who insist that she shouldn't allow her sons to play with toys or wear clothes traditionally labeled as "girly." She has also received praise though for letting her kids be exactly who they want to be. Farias wrote in her post that if more parents combatted gender stereotypes, colors would simply be colors for all kids to enjoy and wear.