The Catholic Church has issued an official document rejecting the idea that you can decide if you are a man or a woman.
The Vatican paper insists that the sexual complementarity of men and women is to make babies.
Published during LGBT month, the document was quickly rounded upon by LGBT Catholics who said it contributed to bigotry and violence against gay and transgender people.
Advocacy group New Ways Ministry said it would further confuse individuals questioning their gender identity or sexual orientation and at risk of self-harm.
The text, Male and Female He Created Them, was intended to help Catholic teachers, parents, students and clergy address what the Vaticans Congregation for Catholic Education called an educational crisis in the field of sex education.
It called for a path of dialogue and listening on the issue of gender theory in education. But even priestly advocates for LGBT Catholics noted that the text appeared to have relied entirely on previous papal pronouncements, Vatican documents and philosophers and theologians.
Jesuit priest and author James Martin said: The real-life experiences of LGBT people seem entirely absent from this document.
We should welcome the congregations call to dialogue and listening on gender, and I hope that conversation will now begin.
Jay Brown of the Human Rights Campaign – the largest LGBT-rights group in the United States – said the Vaticans stance sends a dangerous message that anybody who experiences gender diversity is somehow less worthy.
Pope Francis has repeatedly argued the position that people cannot choose their genders. But the document represents the first attempt to put the Vaticans position, first articulated fully by Pope Benedict XVI in a 2012 speech, into a comprehensive, official text.
The document called for a new alliance among families, schools and society to offer a positive and prudent sexual education in Catholic schools so children learn the full original truth of masculinity and femininity.