HARTFORD, Conn.  —  The state Supreme Court has denied a conservative group's request to intervene in a lawsuit seeking to legalize gay marriage in Connecticut.

The court decision, released Monday, upholds a lower court's ruling denying the Family Institute of Connecticut's motion to intervene.

Eight gay couples are challenging the constitutionality of the state's marriage laws, saying they treat gay and heterosexual couples differently.

The Family Institute wanted legal standing to present evidence that it says shows children are hurt by living in gay and lesbian homes.

Connecticut recently became the first state to offer civil unions without a court order, but the couples involved in the lawsuit argue that civil unions are not equal to full marriage.