The Family Research Council has raised concerns over one of the first executive orders to be issued by Joe Biden after taking office on Wednesday.
The executive order prohibits discrimination on the basis of sexual orientation and gender identity, and orders federal agencies to review their policies and update them where necessary.
In line with the executive order, the White House updated its contact form on the day Biden took office so that individuals must state their preferred pronouns when they submit a comment.
"Children should be able to learn without worrying about whether they will be denied access to the restroom, the locker room, or school sports," the order reads.
"Adults should be able to earn a living and pursue a vocation knowing that they will not be fired, demoted, or mistreated because of whom they go home to or because how they dress does not conform to sex-based stereotypes.
"People should be able to access healthcare and secure a roof over their heads without being subjected to sex discrimination. All persons should receive equal treatment under the law, no matter their gender identity or sexual orientation."
FRC President Tony Perkins said the order contradicted the president's call for unity in his inauguration speech and that Biden now appeared to be "demanding uniformity".
He fears that faith groups will lose government contracts if they don't conform, and that the order will have far-reaching consequences for individual Americans with a conservative view on sex.
"President Biden's executive order effectively targets people of faith and faith-based organizations that provide social services that are even more vital in the midst of a pandemic," he said.
"Now, those who hold to biological reality and the doctrines of the world's major religions will be forced to violate their consciences, or even lose a government contract.
"Ultimately, if this executive order is able to be fully carried out, it will affect everyday Americans who hold biblical and conservative values."
Mr Perkins predicts that the Biden administration is likely to go "much further in its assault on biological reality" and will soon force schools to permit biological males to compete as girls, and use the facilities of their choice.
"The party that claims to be the party of science is advancing policies on day one that deny reality," Perkins said.