Mero, who serves on the congress' management committee and used to work for The Howard Center for Family Religion and Society, which founded the Congress, said Salt Lake City is the perfect place for the conference.
"I think there's no better locale more focused on family as the fundamental unit of society than Utah," Mero said. "I think Utah is exceptional in faith, family and in freedom."
Attempts to reach leaders of the World Congress of Families a periodic event more than an organization for additional comment Tuesday were not successful.
But its website explained the natural family as "the fundamental social unit, inscribed in human nature, and centered on the voluntary union of a man and a woman in the lifelong covenant of marriage.
"The natural family is defined by marriage, procreation and, in some cultures, adoption. Free, secure and stable families that welcome children are necessary for healthy society. The society that abandons the natural family as the norm is destined for chaos and suffering."
Jason Rahlan, global press secretary for the Human Rights Campaign, a lesbian, gay, bisexual and transgender (LGBT) civil rights organization, noted that the Southern Poverty Law Center has labeled the World Congress of Families as a "hate group."
"Hate is not an American value and the World Congress of Families must stop exporting their vicious brand of anti-LGBT bigotry abroad," Rahlan said. "We feel it's important the citizens of Salt Lake City know how dangerous they are and that they're coming to town very soon."
Brandie Balken, executive director of Equality Utah, said her group is also concerned about the plans for a gathering in Utah.
"The World Congress of Families has built an organization that distorts 'traditional values' to exclude, demean and vilify others propagating a narrow view of what it means to be a family," Balken said in a statement. "Their approach and goal seems to be in direct contrast to the concerted efforts of most Utahns in creating a state which welcomes the world."
Steven Ha, executive director of the Utah Pride Center, said those who attend the congress have a right to express their opinions, but he hopes those views don't lead to violence or further discrimination against LGBT families.
He said the 10th Circuit Court of Appeals' recent ruling that a Utah judge was right to lift the state's same-sex marriage ban does not interfere with the rights of non-LGBT families.
Mero, however, said the gathering will be a chance to celebrate traditional marriage, not an attack on gay marriage.
"I think that overlaps with the general concern with the LGBT community that anything that celebrates traditional marriage or family as the fundamental unit of society is seen as a threat to them," Mero said.
The group has long had ties to The Church of Jesus Christ of Latter-day Saints. LDS apostle Dallin Oaks is an honorary member of the congress' board of directors. Also, late Brigham Young University law professor Richard Wilkins ran the World Family Policy Center, which co-sponsored a congress in 1999 in Geneva.
Church spokesman Dale Jones said in a statement of the upcoming conference, "Although the church wasn't involved in the decision of the World Congress of Families to come to Salt Lake City we appreciate the efforts of organizations working to strengthen the family and society."
A gathering in Russia had been set for September, but was cancelled because of logistical difficulties arising from the situation in the Ukraine and Crimea and the resulting U.S. sanctions, according to a news release.
"At a time when Western governments are moving backward to a pagan worldview, Russia has taken a leadership role to advance the natural family," that March news release said.