On Tuesday the California Supreme Court will have a hearing on the constitutionality of the state law defining marriage as the union of a man and a woman.

This action was triggered by gay-rights groups who want marital equality while on the other hand opponents are threatening with a counterattack.

Those who support the same sex marriages appeal to the commitment of the state to equality no matter the gender or sexual orientation, the needs of the children of gay and lesbian couples, the social discrimination and other legal rights like the freedom of expression, association and privacy.

The state has already taken measures toward this direction regarding the equal rights for gays and lesbians and the power of politicians and voters to determine state policy.

The groups who oppose the same sex marriages are asking the court to justify the state law on moral or scientific grounds, as an assertion that matrimony is limited only to a man and a woman and that is best for the children and the society.

A decision will be reached within 90 days.

The case is formed out of four lawsuits: three from almost two dozen couples who want to marry and the fourth by the city of San Francisco, which got involved after Mayor Gavin Newsom's order to let almost 4,000 couples of the same sex to get married in February and March 2004 was annulled by the court.

The lawsuits are based mainly on the California Constitution which is more protective of individual rights rather than the U.S. Constitution, according to state courts.

The plaintiffs appeal to passage in the 1948 about interracial marriage, the first of this kind in a state’s high court. In the passage the justices recognized a "right to join in marriage with the person of one's choice."

Judge Richard Kramer of San Francisco Superior Court appealed to it in March 2005. He ruled that the ban on marriage of the same sex violated "the basic human right to marry a person of one's choice." But in October 2006 the court rejected his findings saying that the historic definition of marriage may be kept while actions can be taken in order to protect the rights of same-sex couples who are registers as domestic partners.