Same-sex marriage rights got an endorsement Monday from four Vermont professional organizations who cited research findings that “children of lesbian and gay parents are as likely as those of heterosexual parents to flourish.”

They also said gay and lesbian parents are as likely as their heterosexual counterparts to provide healthy environments for children and that “there is no credible scientific evidence” relating parenting effectiveness to sexual orientation.

Their statement, which comes as the Vermont legislature prepares to consider same-sex marriage legislation, was released at a news conference called by the Vermont Psychological Association, the Vermont Psychiatric Association, the Vermont Association of Mental Health Counselors and the Vermont chapter of the National Association of Social Workers.

Speaking on the organizations’ behalf, Jackie Weinstock, an associate professor in the department of integrated professional studies at the University of Vermont, said the groups wanted to “set the record straight” by rebutting contentions by gay-marriage opponents that children raised by single-sex parents fare less well than their counterparts in heterosexual families.

“No study has shown that outcomes for children of single-sex families are any less positive than outcomes for children in heterosexual families,” Weinstock said. She said contrary findings sometimes cited by opponents apply in part to children of divorced parents, not exclusively to children of single-sex parents. She acknowledged that national studies of children in same-sex parents have been limited by small research samples. See Professional groups back gay marriage BurlingtonFreePress.com