A new line of onesies and children's t-shirts is starting kids out on their activist journey at a young age.

Little Activists, which launched its first collection in January, is using clothing to help children engage with modern social issues, like environmental protection, LGBTQ rights, and anti-bullying. The shirts feature cheeky, kid-friendly messages that put equality and progress in the spotlight.

SEE ALSO: 9 tips for raising a socially aware child

One shirt, for instance, says, "I root for trees." Another has the message "Eracism" to fight racial bias and discrimination. The goal through all the shirts, the creators say, is to encourage kids to be accepting, inclusive, thoughtful, and kind.

"We care about the world around us, and are not afraid to say what we think," one girl says in a video for the brand.

❤️✌🏼Take the lead with a good deed. Be the first person to stand up to a bully. #upstander #littleactivists #stopbullying #bullyproof #antibully #hugsnoth8 #nobullyzone A post shared by Little Activists (@littleactivists) on Feb 28, 2017 at 9:09am PST

So far, Little Activists has come out with three lines sold online: Lil' Rebels, the Eco-Collection, and Be Cool, Be Kind.

The company was founded by Tia Clarida and Kim Lieb, two seasoned marketing executives and mothers who hope to give children a way to express what they're feeling or noticing about the world around them. The pair also created the stylish shirts to help parents open a dialogue about social issues with their children at an early age.

A post shared by Little Activists (@littleactivists) on Jan 17, 2017 at 9:38am PST

"I was constantly on the hunt for cool t-shirts for my son, but was always disappointed in the uninspiring messages," Clarida said. "One night, I had an epiphany: to create cool, fun t-shirts that talked about modern-day issues from a place of positivity."

At 1:30 a.m., Clarida hopped out of bed and bought the domain littleactivists.com. She then enlisted Lieb to help her create a business plan the very next day.

Image: Little Activists

Little Activists ran a beta version of its line last summer, and responded to customer critiques and comments to finalize the designs and messaging. After a bit of redesigning and refining, the company launched in January — and business has been booming.

Unlike the majority of children's clothing, which has broad appeal regardless of a family's beliefs, Little Activists is plugging into a specific demographic with its line: progressive families. Speaking to that core audience is where the company is finding success, despite the hesitance of some parents to talk with children about heavy social issues.

"We know that we can’t be everything to everyone, and these products may not appeal to certain demographics," Lieb said. "But speaking to those people who strongly believe in freedom of expression, gender equality, human rights, animal rights, anti-bullying, and simply making the world a kinder, more inclusive place are our demographic. It truly has been an incredible journey so far."

Clarida and Lieb are currently developing a line of shirts for teens and an accessory line for all ages. They're are also pitching to retailers, hoping to make the jump offline and into children's clothing stores around the U.S.

WATCH: Are schools bullying trans students?