At their first meeting they held hands nervously, played with their dolls to break the ice and then wouldn't let each other go. The three-year-old girls, Mia Funk from Chicago and Mia Ramirez from Miami, looked and acted just like sisters.
Now, in a remarkable tale of coincidence and discovery beginning in a Chinese orphanage and ending in an emotional reunion sparked by some Internet sleuthing, two sets of parents are working out how to bring up the twin girls living 2,200km apart.
"It has to be a miracle of God," said Douglas Funk, the adoptive father of the girl he and wife Holly named Mia Diamond before bringing her to a new life in the US two years ago.
"What are the odds that of all the people in China these two are sisters? What are the chances of the two of them getting together to find each other? It's amazing," he said.
The girls were taken in, separately and unidentified, by the children's welfare institute in Yangzhou, Jiangsu Province, after they were abandoned a week apart.
It was only when Diana Ramirez of Pembroke Pines, a Miami suburb, wrote about her daughter Mia Hanying's forthcoming birthday on an Internet site for parents who had adopted from the orphanage that Mrs Funk saw the message and began to wonder.
E-mails were exchanged, followed quickly by DNA tests that showed an 85 percent likelihood the girls were sisters. With unidentified parents this is the highest possible reading.
"We found out that they had the same name and they were both three years old," Mrs Funk said. "We swapped pictures and they looked so much alike. Then we found out they were found at the same spot."
After chatting several times on the phone, the twins wore matching Chinese outfits for their first face-to-face meeting at Chicago's O'Hare international airport. They stared at each other in fascination before tentatively holding hands and gradually becoming friends as they played with dolls and a musical lamb that Mia Diamond brought as a present for her sister.
While the reunion brought joy, both families realize it will also create hardship as the fraternal twins grow up so far apart from each other.
"It's a little bit of a distance, but whenever we can we'll get together," Mrs Ramirez said.
"It's like an in-law situation with the Ramirezes and us, we're going to be family," Mrs Funk said. "We plan on letting them get to know each other."