The effort is backed by the Utah Pride Center, Equality Utah and Affirmation, a support group for gay Mormons.
Michael Otterson, managing director of public affairs for the LDS Church, said the faith shares "common ground" with HRC in its desire to stop anti-gay bullying.
"We have all witnessed tragic deaths across the country as a result of bullying or intimidation of gay young men," Otterson said at a news conference, referring to a string of suicides the past month. "We join our voice with others in unreserved condemnation of acts of cruelty, or attempts to belittle or mock any group or individual that is different whether those differences arise from race, religion, mental challenges, social status, sexual orientation or for any other reason."
Lori Davis, a Draper mom, said such statements help create a safe place for her pre-adolescent son within the LDS Church. She considers her son to be "gender nonconforming." He likes to play with American Girl dolls and jewelry. He has expressed preferences for feminine things since he was 2. Whether he ends up being gay or straight, she wants him to know he is loved.
"I was so impressed with [Otterson's] statement. I just felt like the church was really providing some support, finally, for me and my family," said Davis, who is active in the LDS faith but disagrees with many of its teachings on same-sex attraction. "When it really comes down to it, that's the only thing we need love and support."
Otterson encouraged LDS families and individuals to speak out against unkindness they witness toward people with same-sex attraction. Experiencing such attraction is not sinful under Mormon doctrine, he said, but it is a sin to act on those feelings.
He reiterated the church's opposition to same-sex marriage. "Our doctrinal position is clear: Any sexual activity outside of marriage is wrong, and we define marriage as between a man and a woman."
But HRC spokesman Michael Cole said Otterson's comments failed to correct Packer's "inaccurate and dangerous statements."
"Science tells us that same-sex attraction is completely normal," Cole wrote in an e-mail, "and that it can't be changed."
Last year, the American Psychological Association passed a resolution advising mental health professionals against telling clients they can change their sexual orientation through therapy or other treatments. No solid evidence exists that such efforts work, the APA concluded, and some studies suggest a potential for harm.
The "long-standing consensus" of the behavioral and social sciences, the APA noted, is that homosexuality is a "normal and positive variation of human sexual orientation."
Last week, Packer edited his speech, delivered at the LDS Church's 180th Semiannual General Conference, for online publication to more closely reflect the faith's view that the cause of same-sex attraction is unknown and the only sin is acting on those desires.
The changes didn't satisfy Packer's critics, but thousands of people have endorsed the senior apostle and his speech online. More than 24,000 have pledged on Facebook to write to Packer and share their support for his speech and his position as a "prophet, seer and revelator" for the LDS Church. The goal is to gather 100,000 letters. A separate, "I support Boyd K. Packer," Facebook page has more than 13,000 backers.
Valerie Larabee, executive director of the Utah Pride Center, said she is pleased that Otterson continued the "dialogue" between the LDS Church and the lesbian, gay, bisexual and transgender (LGBT) community. But she still worries that teaching that same-sex behavior is sinful causes disruption in families.
"There are still a lot of things unanswered about how families that have LGBT loved ones are having these conversations in their homes," Larabee said. "To a young person [who] is seeking a safe place to talk about who they are, it would be a lot to hear that you can't be all of who you are and still be with the rest of your family."
LGBT youths who experience high levels of family rejection are eight times more likely to attempt suicide, six times more likely to experience depression and three times more likely to use illegal drugs than those who don't, according to a 2009 report in the medical journal Pediatrics.
They also are more likely to run away or be expelled from home than non-LGBT youths. In Salt Lake City, 42 percent of homeless youths, ages 15 to 22, are LGBT, according to a survey last year at the Homeless Youth Resource Center. About 8 percent of Salt Lake City's population is LGBT.
The text of Human Rights Campaign's letter to Boyd K. Packer
"I'm appalled that you chose this moment to deliver a sermon saying same-sex attraction is unnatural and same-sex unions are immoral. You have risked further alienating LGBT youth and potentially contributing to suicides of even more vulnerable young people. You've told them that their very identities are 'impure and unnatural,' and you've incited the violence and bullying that often drives them to suicide by repeating lies disproven by both science and the experience of millions of Americans who know their LGBT neighbors and care about them.
"I hope you will cease putting young people in real peril and acknowledge the scientific truth: Sexual orientation cannot be changed, nor should it be."
Signed by HRC President Joe Solmonese and 150,000 others
Excerpt from LDS spokesman Michael Otterson
"The church recognizes that those of its members who are attracted to others of the same sex experience deep emotional, social and physical feelings. ... Their struggle is our struggle. Those in the church who are attracted to someone of the same sex but stay faithful to the church's teachings can be happy during this life and perform meaningful service in the church. They can enjoy full fellowship with other church members, including attending and serving in temples, and ultimately receive all the blessings afforded to those who live the commandments of God."