But after a series of hearings, the Court of Appeals in Albany ruled unanimously that because Mrs Truong’s mother is her husband’s half-sister, and the siblings do not share a father, the genetic risk to any children born to the couple was no more than that between first cousins, who are free to marry.
Announcing their decision, Judge Robert Smith said: “First cousins are allowed to marry in New York, and I conclude that it was not the Legislature’s purpose to avert the similar, relatively small genetic risk inherent in relationships like this one.”
At the time of their wedding, Mr Truong was 24 and his bride 19. In 2007, an immigration judge had ruled that the marriage was bogus and ordered Mrs Truong be deported back to Vietnam.
But the couple appealed, and a federal court asked New York’s highest court to rule on whether their union was permissible under state law.
The judges declared that while marriages between uncles and nieces or aunts and nephews were expressly forbidden, there was no such prohibition on half-uncles and half-nieces becoming husband and wife. Like first cousins, those in such unions will share an average of around one-eighth of the same DNA.
The ruling added that while “parent-child and brother-sister marriages … are grounded in the almost universal horror with which such marriages are viewed … there is no comparably strong objection to uncle-niece marriages.”
In addition, the judges said, the: “genetic risk in a half-uncle, half-niece relationship is half what it would be if the parties were related by the full blood.”
The couple’s attorney Michael Marszalkowski welcomed the decision, saying: “It really was the equivalent of cousins marrying, which has been allowed in New York state for well over 100 years.