Rolling Stone tells of a rash of suicides among lesbian/gay/bisexual/questioning teens in a conservative town in Minnesota. They mention a next generation sex education program in public schools sponsored by evangelical organizations that questions same sex attraction. This heterosexual-only sex education program appears to be just another guise of abstinence-only sex education, and it seems to follow from the same motivation.
Both programs come from an assumption that both same sex attraction and premarital sex are brand new phenomena, and that it's possible to go back to the way things used to be. (Of course, plenty of evidence indicates that they're not new, and even if they were new, it's neither possible nor desirable to go back to a time when women's suffrage was unthinkable. None of the strong women evangelical leaders would agree to reverse feminist gains.)
Both programs attempt security via obscurity, and treat education as dangerous. Teaching a subject (contraception or same-sex attraction) is thought to encourage and legitimize the subject, and to advance an imagined liberal agenda.
Instead, the programs just delegitimize normal behavior and endanger teenagers. Abstinence-only sex education increased unsafe sex probably because it taught that pregnancy and STDs were unavoidable, so there was no point to avoiding them. Alternatively, it made teens so worried about the spiritual effects of sex that they never worried about the physical effects. That's dangerous and bad for public health, but probably no one would die from it. Hetero-only sex education is more insidious because it further marginalizes a population that is already marginalized, at high risk for educational and health disadvantages, and at high risk of suicide.
Right now these hetero-only sex education programs are coming into public schools using private funds. That's how abstinence-only sex education started in the early/mid 1990s. The next stage would be to slip funding for these programs into another bill, as abstinence-only began in 1996 with the welfare reform bill. I hope it doesn't get that far.