The findings of the studies are contradictory and both studies are valid.
The Annenberg Center for Policy Research presented a study at the 06 International AIDS Conference in Toronto based on randomized controlled trials of statistically significant number of teens in Philadelphia.
The findings of the Mathematica study suggests that abstinence only programs are ineffective, the Annenberg study suggests the opposite.
Congress, faced with the dilemma of contradictory research findings often splits the difference and develops policy that is neither fish nor fowl.
In reaction to the political heavy handedness of abstinence only programs' political supporters there is a growing movement to reject them. In my opinion this is a mistake.
I personally know forty some public school kids who take abstinence seriously and whose positions have been validated by their schools' sympathetic explanations of abstinence.
Abstinence does not work for every kid, but numerically it probably remains the most used form of sexual behavior.
If abstinence is consistently applied it will prevent not only pregnancy and STDs, but also the adverse socio-economic effects of teen sex.
Clearly, abstinence must be a voluntary and uncoerced commitment.
But if a teen makes such a commitment, abstinence instruction provides a support network.
Abstinence is not about avoiding sex- it is about building character.
Believe it or not, kids won't die if they wait on sex until they are mature enough emotionally and socially to handle it.
Progressives should not cede ethical and principled forms of sexual conduct, such as abstinence to the religious right.