Crowded into a science classroom in her Texarkana middle school, Parker Ellyn Madlock and her seventh-grade classmates watched as their sex education teacher held up two Butterfinger candy bars.

Then the teacher unwrapped one and took a bite, asking the students which one they would pick if they were offered a choice between the two. None of her female classmates — boys were in a separate room— said they would eat the half-eaten candy bar, recalls Madlock, now 20.

“It felt like that was saying ‘If you have sex now or anytime soon, no one’s gonna want you,” said Madlock, a sophomore at Ouachita Baptist University. “Wait until you’re married, girls, or else.”

Madlock’s experience is nothing new. Texas sex education is required to stress abstinence above all else, with health standards that have remained untouched for more than 20 years. A major review by the State Board of Education, the ultimate authority on Texas public school curriculum, could change them next year — or not.

Advocacy groups have long documented examples of “fear and shame-based instruction” in Texas that they say lack unbiased information about contraception and sexually transmitted diseases.

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They point to the state’s high teen birth rate and a national study from 2008, which concluded that adolescents who received comprehensive sex education had a 50 percent lower risk of teen pregnancy than those who received abstinence-based education.

But Texas officials have already signaled a degree of reluctance to even add a few lessons on contraception to the curriculum, as some parents and educators worry that instruction on birth control will only propel students toward risky behavior.

At a conservative forum earlier this month, Stephanie Curry, a public policy manager with the religious organization Family Policy Alliance, said comprehensive sex education is linked to a liberal agenda.

“Comprehensive sex education is not education, it is indoctrination,” Curry said. “It teaches our children that they are sexual beings from birth … It will teach them they can have sex with anyone, LGBT, whenever they want.”

In the meantime, bitten-off Butterfingers aren’t the only candy-based abstinence lesson in Texas public schools.

For subscribers: Rewrite of Texas sex education standards could include lessons on contraception

At Leander Independent School District just outside of Austin, Cailyn Stewart and her middle-school classmates were given Skittles and instructed to swap them with each other. After the candy made the rounds, passing from hand to hand, the teacher asked if anyone wanted to eat it.

When nobody did, the teacher told them this was how sex, and sexually-transmitted diseases, work.

“Would you eat that Skittle?” Stewart, now 20 and a student at the University of Texas at Austin, recalls her teacher asking. “No, it's dirty, it has germs on it, it wouldn’t be sanitary. It kinda gave us the insinuation of the more people you have sex with, the dirtier you are.”

At her high school in Leander, Cassie Heath, 22, remembers her teacher crumpling up an artificial flower while telling female students the flower represented their bodies before and after sex.

“They were borderline traumatic ideas about your body’s worth, and even if you rejected it then, it’s in your head now,” said Heath, now a student at Texas State University. “For me, it created such a shame around having sex.”

Birth control, and local control

With over 1,200 school districts in Texas, what students hear in their science classrooms and health seminars can vary wildly, even in the same school.

The discrepancies boil down to Texas policy. The Texas Essential Knowledge and Skills health standards don’t require schools to teach sex education at all. If schools choose to, however, state law requires them to emphasize abstinence as the preferred behavior and devote more time to it than anything else. Information on contraception methods is not required.

With no state-mandated curriculum, districts wind up choosing from several popular programs offered by independent contractors or using state-approved health textbooks. Many of these offer the bare minimum of abstinence-based instruction.

Some include analogies that seem like springboards for the candy-based abstinence lessons. According to a 2012 report in the Journal of Health Education Teaching, the sex education curriculum WAIT Training tells teachers to stick a piece of clear tape on a student’s arm, then pull it off and point out how the tape loses its stickiness each time it is reapplied to the skin.

Related: Are we really teaching sex education in Texas?

Jennifer Driver, a state policy director with the Sexuality Information and Education Council of the United States, said the effects of fear- and shame-based instruction can be dire. Texas has seen high rates of suicide and sexual assault, which can be attributed in part to “harmful” messages spread in schools, she said.

“It’s baffling to me. It’s not only scarring, it’s shaming young people away from honest questions about their sexual and reproductive health,” Driver said. “There’s facts and evidence, and then there’s ideology. I think nationally, we’re failing our young people, but Texas also has a long way to go.”

A 2017 Journal of Adolescent Health report scrutinizing abstinence-only programs across the U.S. concluded those programs largely “stigmatized” students who are not heterosexual and contributed to adolescent health problems including suicide and risk for HIV infection.

For years, troubled by high rates of teen pregnancy and sexually-transmitted disease, state health experts have called for changes that better reflect national standards of comprehensive sex education, including focus on contraceptive measures, gender identity and LGBTQ inclusion.

It seemed like Texas was taking some lessons from comprehensive sex education in June, when Commissioner of Education Mike Morath recommended that students learn “sexual risk reduction methods that may be needed later in their lives,” presumably contraceptive measures.

Texas has consistently had one of the highest teen birth rates in the nation, coming in at No. 7 in 2017, according to data by the Center for Disease Control. And the number of Texas teens involved in “risky behaviors,” such as unprotected sex, is greater than the national average, according to Morath’s report.

State board-appointed content advisers drafted their own recommendations in August. The recommendations don’t change the abstinence policy. But they do request instruction around contraception be modified — by telling students more directly about the risks and failures associated with birth control.

If any revisions are ultimately approved, it will be the first change since 1998. Final votes will take place in September of 2020 and approved curriculum will be rolled out by 2022.

Ken Mercer, a Republican state board member who represents part of Travis County, said candy-based abstinence lessons are not ideal. But he pledged to guard against what he sees as radicalization of the curriculum.

“We don’t want Skittles or Butterfingers, maybe there needs to be more language, but we don’t want a how-to manual,” Mercer said in an interview. “Girls in Texas are not sluts, we don’t need to tell them to have sex. But I want girls to have information, it gets back to that — I want kids to be informed.”

Some teachers just avoid it

Donna Hunt, a veteran biology teacher in Bowie County, has taught sex education for at least a decade. Since the state doesn’t require her to teach any particular curriculum, or really even address sex education at all, Hunt has developed her own methods. The candy bar analogy is one of them.

She says the lesson isn’t meant to shame anyone — rather, it’s intended to emphasize the idea of choice in a way 12-year-olds can understand.

“We never want to be inaccurate about biology,” Hunt said. “The point was to disassociate children’s bodies from the sex education, especially when we’re talking about choosing to have sex.”

Hunt is open about her faith-based approach to teaching the TEKS health standards and said she doesn’t want “any radicalized community” coming in to revamp the curriculum. She says abstinence should always be the baseline.

“Now if you pull abstinence away, you’re basically teaching them that when you have these impulses, it’s OK to act on them as long as you’re doing them safely,” Hunt said. “But if you’re going to act on this impulse, what other impulses are OK to act on? That’s my concern.”

Hunt said teachers need more concrete requirements for teaching sex education, and more detailed instruction on contraception.

Hunt has worked with science teachers who avoided sex education as much as possible. While she was having discussions with students and teaching the basics of using a condom, other teachers would have a few slides on abstinence and common STDs and discourage questions.

Lauren Carter, now a 20-year-old college student in Arkansas, had her sex education as a seventh-grader as well, down the hall from Madlock’s classroom. She said her teacher offered few details, and virtually no discussion of contraception, its benefits or risks.

When Carter got pregnant three years later at 15, she said she didn’t know how easily it could happen. She was unaware of what her symptoms meant for nearly six months.

“I didn’t get any birth control, I didn’t know how to go about doing anything,” Carter said. “I was 15. I was blindsided. We were supposed to learn that stuff. When you really think about it, that sucks that I made life-altering decisions and school was supposed to educate us about that-and didn’t.”