TWO young boys playing at a pool last summer discovered they looked incredibly similar - they even had the same walk.

But Isaac Noltin, 12, and Dakotah Zimmer, 13, were in for the shock of their lives to discover there was more than met the eye with their similar appearances: they were brothers.

Dakotah told Isaac that he knew he had a brother he'd never met who was adopted by a woman named Dawn. "That's my mum's name," Isaac responded.

The touching story of how Dakotah and Isaac met is one of anxiety for Isaac's adoptive mother, Dawn Noltin.

Ms Noltin, who works as a manager for a dry-cleaning company, had wrestled with when to tell her son that he was adopted.

For weeks before Isaac and Dakotah met, she had been asking her friends and pastor how to tell her son that he had a brother, but knew it had to be before the boys went back to school.

They would be attending the same middle school in Washington, Missouri, and would surely find out one way or another.

The night after Isaac and Dakotah met, Isaac approached his mother and asked if he was adopted. When Ms Noltin, 42, asked why he thought that, her son responded: "Because I think I found my brother."

Mother and son both began crying. "I was so happy that I had a brother," Isaac said. "I had always asked for one."

Ms Noltin had met Isaac's mother several years ago when she was heading out to dinner with her ex-husband. A friend of Ms Noltin's ex invited them to meet his girlfriend and their newborn son.

The 16-year-old mother had just given birth to Isaac nine days before, and also had a one-year-old son Dakotah. Ms Noltin had been a single mother herself, having her own daughter at 19.

She said her maternal instincts kicked in, and she offered to take care of the newborn. Months passed, and Ms Noltin received a call that Isaac's biological mother was pregnant again.

The woman's grandmother asked if Ms Noltin wished to adopt Isaac. Eighteen months later, Isaac was legally hers.

Isaac and Dakotah's biological mother died in 2007, and their biological father died a year later.

Dakotah and his older sister, Ashley, live with their and Isaac's biological grandmother, Debi Bay.

Ms Bay said Dakotah always knew he had a brother. "I'm just glad they got to meet," she said.

Though the two didn't know of each other's existence for a decade, it seems as though they grew up together, Ms Noltin said.