One year after woman was mistakenly given someone else's newborn, her baby comes home

When Mercy Casanellas laid eyes on her baby after her emergency Caesarean last year, it was love at first sight. He had her sharp nose, her husband's blue eyes. Then, because he was born prematurely, he had to spend the night at the specialist ward.

"He was just passed by me and I gave him a kiss and then he was taken to the nursery and that was the last time I saw him," Casanellas told the BBC.

The next day, the baby who was returned to her looked different - he had a darker complexion. Casanellas told the nurses, "This is not the baby I saw last night."

Casanellas, who met her British husband Richard Cushworth at a Texas missionary school, had returned to her native El Salvador to give birth. The hospital staff insisted that it was the same baby, so the couple relented. They named the baby Jacob and took him back home to Dallas.

For a couple months, Casanellas cared for Jacob and came to love him dearly. But she couldn't shake the suspicion that he wasn't really hers.

She decided to take a DNA test, although doing so left her wracked with guilt. "I thought I was betraying him," she told the BBC. "That was the feeling I had - I'm betraying my son but I cannot live with this."

The test results revealed there was a less than 1 percent chance that she was Jacob's biological mother.

"I fell on the floor," Casanellas told WFAA. And then she wondered: "Where's my baby?"

So began a year-long fight to find her actual son and bring him home. Even after the Casanellas and Cushworth were reunited with their own baby in El Salvador, immigration hurdles prevented them from bringing him back to the US for another nine months. He entered the country for the first time this week.

The family walked into the arms of waiting relatives at the Dallas/Fort Worth International Airport, as a smiling Casanella held her son.

It was a belated homecoming.

"Overwhelming," Cushworth told WFAA. "This has been a long process."

It started with switching the babies back. After alerting the authorities in San Salvador, the couple was connected with the parents who had their child. By that time, the babies were four months old - they had spent a third of their first year in mistaken families.

Despite their joy at seeing their baby again, the couple was anguished to let Jacob go.

"I think that was the most difficult part," Casanellas told WFAA. "We raised him like ours."

When the couple received their own baby, they gave him a new name: Moses. But the ordeal didn't end there.

Because Cushworth is British and Casanellas is Salvadoran, they had to procure extensive paperwork before the El Salvador government granted them Moses's birth documents to travel to the U.S. The entire process took nine months, according to the BBC, and caused the couple considerable financial stress.

After all that, it remains unclear how the mix-up occurred.

The gynecologist who delivered Moses, Alejandro Guidos, had been arrested, but charges against him were dropped earlier this month. CNN reported that Salvadoran authorities were spurred to review protocols in hospitals to prevent a similar occurrence in the future.

Now, Casanellas is just relieved to be reunited with the son she birthed.

"There are no words to express what our heart feels to have our baby at home!" the couple told CNN. "Thanks to all who joined our pain and fed our hope."