A group that opposes gay marriage asked the U.S. Supreme Court on Wednesday to take up a challenge to Nevada's ban on same sex unions. The Coalition for the Protection of Marriage said the case crystalizes the fundamental question of whether the legal definition of marriage should be changed from a man and a woman to the union of any two people. The coalition filed documents seeking what is known as a writ of certiorari that asks the Supreme Court to take the case before it can be considered by the 9th U.S. Circuit Court of Appeals in San Francisco. The Lambda Legal Defense and Education Fund vowed last week to appeal to the 9th Circuit a federal judge's ruling in Reno that Nevada has a "legitimate state interest" in prohibiting the recognition of same-sex couples. Lambda attorney Tara Borelli, in Los Angeles, said she will oppose the coalition petition and officials with the gay rights organization doubt the Supreme Court will take up the case. The coalition, based in Boise, Idaho, opposes gay marriage and was involved in the Nevada case. Monte Stewart, a lawyer for the group, declined comment on the effort to have the Supreme Court intervene. "The fundamental marriage issue is whether ... the legal definition of marriage (should) be changed from the union of a man and a woman to the union of any two persons," the coalition filing said.