ANNAPOLIS, Md. — As many as 300 supporters and opponents of a bill to legalize same-sex marriage in Maryland packed the halls of a State Senate office building in Annapolis Tuesday while several dozen witnesses testified on both sides of the issue.

The Democratic-controlled Judicial Proceedings Committee, which conducted a hearing on the bill, was expected to approve the measure and send it to the full Senate within the next week or two.

A majority of the members of the 11-person committee are co-sponsors or supporters of the bill, the Religious Freedom and Civil Marriage Protection Act.

Most political observers believe supporters have the votes to pass the bill in the Senate and the House of Delegates. Gov. Martin O’Malley has said he would sign the bill.

But opponents, led by Maggie Gallagher, chair of the National Organization for Marriage, said they remain hopeful that supporters would fall short of obtaining the 24 votes needed to pass the bill in the Senate or the 29 votes needed to stop a Senate filibuster.

“Marriage is the union of husband and wife for a reason,” Gallagher said in her testimony. “These are the only unions that can make new life and connect children in love to their mom and dad … If Maryland adopts this radical new view of marriage, it will have consequences,” she said.

Many of the witnesses testifying against the bill — including ministers, an orthodox rabbi, and two Roman Catholic priests — picked up on Gallagher’s view that procreation is the cornerstone of marriage. They said changing the definition of marriage to include same-sex couples would have a detrimental impact on families and society.

An equal number of witnesses, including a Catholic nun and Catholic lay leaders, two reform rabbis and at least a half-dozen Protestant ministers, both black and white, disputed those assertions, saying they believe same-sex unions strengthen rather than harm the family. Many of the witnesses backing the bill identified themselves as people of faith.

“My God loves everyone,” said Elbridge James, a lobbyist for the NAACP and director the Maryland Black Family Alliance.

“My God did not make a mistake,” he said. “And so if you were gay, my God did not make a mistake. If you were lesbian my God did not make a mistake. If you were transgender, my God did not make a mistake. And tonight, when I go home to my wife, nothing will deter me from loving my wife — certainly not if there’s a bill that protects gays, protects lesbians or protects the transgender community.”

Several of Maryland’s gay elected officials testified in favor of the bill. Among them was Sen. Richard Madaleno (D-Montgomery County), a co-sponsor of the bill who has been a longtime advocate for marriage equality in the state. Others included Chevy Chase, Md., Mayor David Loveland and Howard County Register of Wills Byron Macfarlane.

Among Republicans testifying in support of the bill was Sen. Allan Kittleman (R-Howard & Carroll Counties). Kittleman, the former Senate minority leader, initially planned to introduce a civil unions bill as a possible alternate measure to the marriage bill. Two weeks ago, he dropped those plans and announced his enthusiastic support for the marriage measure.

“I stand here as a strong Republican,” he told the committee, adding that he believes marriage equality is in full keeping with Republican principals of individual freedom.

Sen. Brian Frosh (D-Montgomery County), chair of the committee, said at the start of the hearing that more than 140 people signed up to testify.

Their names, organizational affiliation and information on whether they were for or against the bill weren’t immediately available because the committee did not release a witness list on the day of the hearing.

In a procedure unlike the equally packed hearing for a same-sex marriage bill approved by the D.C. City Council last year, the Judicial Proceedings Committee in Maryland required witnesses to sign up in person to testify on the morning of the hearing, preventing the committee from compiling an advance witness list and releasing it to the media.

Based on the testimony delivered during the day, it appeared that the witnesses were about equally divided between supporters and opponents of the bill. As Frosh and Sen. Lisa Gladen (D-Baltimore City), the committee’s vice chair, called witnesses to testify, many were not present, indicating that a significant number chose not to wait their turn to speak at a hearing that lasted more than six hours.

Lisa Polyak, a board member and spokesperson for Equality Maryland, the statewide LGBT organization that coordinated testimony in support of the bill, said the group lined up about 48 supporting witnesses. She said others supporting the bill, including a number of same-sex couples, came on their own.

“We were extremely gratified for all of the families that came out, all of our community partners, and all of the clergy that came out to speak their truth and support us,” she said. “I don’t think we could have had a better diversity of representation.”

Among those testifying was Polyak’s and her partner, Gita Deane’s daughter, 14-year-old Maya Deane-Polyak, a freshman at Baltimore’s Bryan Mawr High School.

“My moms’ first concern has always been my sister and I,” said Maya. “They make sure our every need is met, whether it is helping us with homework, driving us to a friend’s house or merely just being there to cheer us up when we are sad — they do it all and even more.”

Noting that she has witnessed first-hand examples of how her two moms encounter discrimination because they can’t marry in Maryland, she urged the committee to promptly approve the marriage bill.

“So I ask you to please consider, consider the fact that you have the power to change my family’s life when you make your decision,” she said. “I want our moms to be married. You have the power to make that happen.”

Many of the witnesses opposing the bill said broadening marriage to include same-sex couples would weaken the family structure and harm children. Several said children of same-sex parents don’t do as well in school and show greater signs of emotional problems compared to kids of opposite-sex, married parents. LGBT activists have said those assertions are not supported by impartial studies.

Austin Nimocks, senior legal counsel for the Alliance Defense Fund, a conservative litigation group that challenges same-sex marriage laws throughout the country, testified that restricting marriage to opposite-sex couples insures that children are raised by a “stable family.”

He said “responsible procreation” is a key reason why Maryland and other states should not legalize marriage for same-sex couples. By pushing to “redefine” marriage to include gay and lesbian couples “you are telling people that mothers and fathers don’t matter,” he told the committee.

In response to questions by committee member Jamie Raskin (D-Montgomery County), a co-sponsor of the marriage bill, Nimocks acknowledged that some same-sex couples may make good parents, saying “you can find individual circumstances that go against a general rule.”

But other witnesses opposing the bill said there could be no exceptions to their religious-based belief that child rearing by same-sex parents is always harmful to children, both psychologically and spiritually.

“That union of our parents was a sacred right granted to them by almighty God,” said Timonium, Md., resident Gerard Selby. “God’s design for the human race was that it be procreated by the union of a man and a woman.”

He added, “Where do we draw the lines? What comes next? If a man loses his wife to a premature death, shouldn’t he be allowed to marry his daughter, or son, or both?

Leroy Swales, an Oxon Hill, Md., resident who testified last year against the D.C. same-sex marriage bill, told the committee Tuesday that approval of the bill, among other things, would result in Maryland’s elementary schools using the book “Heather Has Two Mommies,” which he called a “pedophile book,” as a teaching aid for students.

Saying that homosexuality is related to an “electrical imbalance of the brain,” he called on the committee to use “science” and biblical scriptures as justification for defeating the bill.