A good post here about the Left's seeming annoyance that any type of abstinence based sex education could possibly work.
The type of programme the subject of this study is described as follows:
As the post further notes:...the study authors looked at African-American middle-school students in the Northeast who enrolled in an abstinence-only program (no instruction on contraceptives) and were taught, sans moral or religious arguments, that they should delay sex until they were ready. Marriage was notably left out of it.
The students in this program were more likely to delay sex in the two years after the program, as opposed to those who enrolled in no program or those who were instructed in safe sex.
The generally negative reaction from the left really gets at how incredibly polarized the sex-education debate has become, to the point where supporters of comprehensive sex education can barely mumble a word of praise for a successful program.