A 16-year-old boy denied a cut of his stepfather's $2.2 million estate because he wasn't born when the man married his mother has won the right to challenge the decision in the Supreme Court.

Alyxe Wood-Luxford was left out of both his mother's and stepfather's wills, which were written before he was born.

Wendy June Luxford, 35, and John Williamson Luxford, 73, of Feilding, died in a three-car pile- up in Taupo in April 2000, when Alyxe was four.

Alyxe's brother, Logan Wood, was left two-thirds of Mrs Luxford's $1.8 million estate and all of Mr Luxford's estate.

Logan was born more than a decade before the couple married.

Since then Alyxe, who has an intellectual impairment, has been embroiled in a legal battle contesting his right to the inheritance.

His principal argument is that New Zealand law is not consistent with other countries in the interpretation of the term "living".

In August the Court of Appeal dismissed a challenge to a High Court ruling that he had no right to Mr Luxford's will because he was not deemed a stepchild under the Family Protection Act. However, a Supreme Court judgement released this morning said Alyxe had won the right to appeal the decision.

Under the act, to be considered a stepchild, a child has to be "living" when his or her parent marries.

That rules out Alyxe, even though he was raised from birth by the couple.

"It was accepted by all parties that Alyxe was in-utero when Wendy and John Luxford married, and John was not Alyxe's father, " the court judgment says.

However, it says he has a "strong claim" to a share of his mother's estate.

- © Fairfax NZ News