Children growing up in lesbian, gay, bisexual and transgender families are more likely to live in poverty and may be denied legal ties to one of their parents, a report released on Tuesday showed.

A lack of federal recognition of same-sex marriages means such families face higher tax burdens and unequal access to health insurance and government safety net programs, said the report entitled "All Children Matter: How Legal and Social Inequalities Hurt LGBT Families."

The report was released online and authored by groups advocating for gay rights including Movement Advancement Project, Family Equality Council and Center for American Progress.

"The reality is if you look at today's modern families, they come in all shapes and sizes," said Jennifer Chrisler, executive director of Family Equality Council.

"The laws and policies we have in place haven't kept pace with that changing reality," she said.

An estimated two million children are being raised in such households, the report said. They live in 96 percent of US counties in racially and ethnically diverse families, it said.

Their children are as happy, healthy and well-adjusted as their peers raised by heterosexual parents, it said.

But such families are more likely to live in poverty than married heterosexual households, the report said.

In 31 states, it is very challenging for same-sex parents to establish legal ties for their children to both parents, Chrisler said. Thus a child could be left vulnerable if a parent dies or the relationship dissolves.

For example, Naz Meftah and Lydia Banuelos were legally married in California and are parents to three young children.

Banuelos is not recognized legally as their parent, cannot sign medical releases for them at the doctor and is not listed on their birth certificates.

The couple participated in the release of the report.

"It's not just sentimental and heart breaking. It has a real impact," Meftah told the reporters. "We are legally married and Lydia is a stranger to her own kids by law."

(Read by Emily Cheng. Emily Cheng is a journalist at the China Daily Website.)