The United Nations is recommending that children as young as five receive mandatory sexual education that would teach even pre-kindergarteners about masturbation and topics like gender violence.

The U.N.'s Economic, Social and Cultural Organization (UNESCO) released a 98-page report in June offering a universal lesson plan for kids ranging in age from 5-18, an

"informed approach to effective sex, relationships" and HIV education that they say is essential for "all young people."

The U.N. insists the program is "age appropriate," but critics say it's exposing kids to sex far too early, and offers up abstract ideas — like "transphobia" — they might not even understand.

"At that age they should be learning about ... the proper name of certain parts of their bodies," said Michelle Turner, president of Citizens for a Responsible Curriculum, "certainly not about masturbation."

Turner was disturbed by UNESCO's plans to explain to children as young as nine about the safety of legal abortions, and to advocate and "promote the right to and access to safe abortion" for everyone over the age of 15.

"This is absurd," she told FOXNews.com.

The UNESCO report, called "International Guidelines for Sexuality Education," separates children into four age groups: 5-to-8-year-olds, 9-to-12-year-olds, 12-to-15-year-olds and 15-to-18-year-olds.

Under the U.N.'s voluntary sex-ed regime, kids just 5-8 years old will be told that "touching and rubbing one's genitals is called masturbation" and that private parts "can feel pleasurable when touched by oneself."

• Click here to see the report.

By the time they're 9 years old, they'll learn about "positive and negative effects of 'aphrodisiacs," and wrestle with the ideas of "homophobia, transphobia and abuse of power."

At 12, they'll learn the "reasons for" abortions — but they'll already have known about their safety for three years. When they're 15, they'll be exposed to direct "advocacy to promote the right to and access to safe abortion."

Child health experts say they are wary of teaching about the sticky topic of abortion, but stress that as long as messages stay age-appropriate, educating kids at a younger age helps better steer them into adulthood.

"The adults are more leery of [early sex-ed] than the kids are," said Dr. Jennifer Hartstein, a child psychiatrist in New York. "Our own fears sometimes prevent us from being as open and honest with our kids as possible."

Hartstein, however, who didn't see much harm in explaining basic concepts that kids of all ages will have questions about, was baffled by some of the ideas the U.N. hoped to introduce to kids as young as 5 years old, who will be taught about "gender roles, stereotypes and gender-based violence."

"I want to know how you teach that to a 5-year-old," Hartstein told FOXNews.com.

Despite those challenges, the U.N. insists that "in a world affected by HIV and AIDS ... there is an imperative to give children and young people the knowledge, skills and values to understand and make informed decisions."

UNESCO officials said the guidelines were "co-authored by two leading experts in the field of sexuality education" — Dr. Doug Kirby, an adolescent sexuality expert, and Nanette Ecker, the former director of international education and training at the Sexuality Information and Education Council of the United States.

Their report was based on a "rigorous review" of sex-ed literature, "drawing upon 87 studies from around the world," said Mark Richmond, director of UNESCO's Division for the Coordination of U.N. Priorities in Education, in an e-mailed statement.

Richmond defended teaching about masturbation as "age-appropriate" because even in early childhood, "children are known to be curious about their bodies." Their lessons, he added, would hopefully help kids "develop a more complex understanding of sexual behaviour" as they grow into adults.

But Michelle Turner, of Citizens for a Responsible Curriculum, said that such roles should be left up to parents, and worried that children were being exposed to too much information too soon.

"Why can't kids be kids anymore?" she said.