On a bright but breezy Texas winter morning at the high school on Clear Creek Road, next to the vast Fort Hood military base, the talk is all about sex.
Or, rather, about how you absolutely must not do it or anything close to it outside wedlock. It is part of the sexual revolution in US schools called Abstinence-Only Until Marriage, a program being cascaded with funding from the administration of US President George W. Bush.
Karen Koehler smoothed her demure skirt, adjusted her green blazer and looked out intently at the class as the 15, 16, and 17-year-olds fidgeted in their seats.
"Give me an example of risky behavior," said Koehler, sex education teacher at Shoemaker High School, Killeen, about an hour north of the state capital Austin.
The teenagers started with easy stuff: "Cheating in tests," called out one. "Smoking," said another. Not what Koehler was after.
"Something to do with sexuality. What about girls in short skirts?" Silence from the class of 25 pupils. "If you wear provocative clothing it makes people think things about you. Guys, what does that say to you -- she is loose? She is easy?" asked the teacher.
The boys tittered. Koehler ignored them: "Girls, how far are you going to take the first date?"
From this educational foreplay, the lesson progressed to the dangers of sexually transmitted infections and an insistence that condoms do not prevent disease or pregnancy.
The climax came with the message now being taught in schools across the US: abstaining from sex until marriage is the only form of protection.The federal government will put around US$170 million into abstinence-only sex education programs in schools this year, a US$30 million increase over last year.
Bush was pushing for the total to go up to US$270 million -- similar to the money spent on the nation's family planning services, which are experiencing cuts as conservative forces crack down on contraception and abortion.
The abstinence funds go to educational, medical or religious groups at local level who devise sex curriculums for the schools.
There is no federal quality control of the material, just the edict to teach abstinence and limit discussion of contraception to failure rates.
At Shoemaker High School they use an abstinence-only course popular across Texas called Worth the Wait -- a trademarked brand.
Koehler continued her lesson by listing the sexual activity that fell in the "danger" category.
"Regular intercourse; anal intercourse; oral intercourse; skin-to-skin under clothes; genital contact; and there are some problems with deep passionate kissing -- these are risky behaviors," she said.
Koehler believes young people are unreliable in their use of contraception.
She is banned by law from promoting the benefits of correctly used condoms.
Bush's home state of Texas, and Florida, where brother Jeb is governor, are two of the largest recipients of federal abstinence-only funding -- around US$7 million annually. Only California and Maine have no abstinence teaching in their state schools.