Wednesday, October 31, 2007

Does the Pill encourage teenage sex? No.

Apologies, this is likely to be a long one

Executive Summary

Blogging on Peer-Reviewed ResearchYou're a busy person, Gentle Reader, so here's the scoop: after a discussion over at Illinipundit, I went looking in the peer-reviewed literature to find out whether or not access to oral contraception increased sexual activity in teenagers. Basically, I was trying to find out whether making oral contraception available encourages teenagers to have more sex. I couldn't find much of anything specifically limited to the Pill, but found quite a lot on contraception in general.

The undeniable conclusion is that access to contraception does not increase sexual activity in teenagers. Similarly and not surprisingly, access to sexual education about contraception also does not increase sexual activity in teenagers. If anything, comprehensive sexual education delays the onset of sexual activity and increases the use of contraception and condoms.


Over at Illinipundit, there was a discussion about a public middle school in Maine with a health clinic that decided to proscribe birth control pills to its sexually active students. Some quick factoids from the NY Times article: there are about 500 students in the school, 135 have the parental permission required to use the clinic, 5 of those were sexually active, and they were all either 14 or 15 years old.

The scope of the teen pregnancy problem is stunning: over 40% of teenage girls are pregnant at least once by the time they're 20. (Kirby) Furthermore, a quarter of sexually active teenagers contract an STD each year. (Kirby)

In the discussion at IP D. Boon asked this:

I would really like to see some of these studies that show the prevalence of The Pill has not led to increased sexual activity at a young age. I have no qualms about saying abstinence only education is probably a not effective, but I've head the opposite about the pill.

Now, I'm pretty sure the research shows that access to contraception does not increase sexual activity in teenagers, but most of what I could remember was about condoms, not the Pill. So I went to look for the actual information.

D. Boon and redstatewannabe both also said that contraception being made available would constitute an "endorsement" of the situation. It was never really explained what that meant, specifically, but I take it to mean that it would have the effect of encouraging teenagers to have sex at a young age.


Google Scholar. Really, that's about it. I searched for various combinations of "oral contraception", "the pill", "birth control", "contraception", "sexual activity", "teenager", "adolescent", and similar terms. I found several of what looked like good papers, read them, and followed their references to papers they cited.

I want to make it clear this wasn't an exhaustive or comprehensive search. Google Scholar isn't the best database out there, and finds lots of extraneous stuff. I'm a scientist and engineer; the databases I usually use don't index this sort of social science material. I know there are other databases like Pubmed and Medline, but I don't know how to use them. I also want to make it clear that I'm not a social scientist, so I'm generally relying on the analysis of the authors (I really don't understand how p-values and statistical significance work). Nor did I want to spend more than an hour or two (or five, by now) on this, so I limited myself to less than a dozen papers.

My search was limited to published, peer-reviewed information and their citations. I specifically did not want to rely on any press reports because they almost inevitably over-simplify the science or get it plain wrong.


In short, neither access to contraception nor sex ed that discussion contraception hasten the initiation of sexual activity. (Committee, Kirby) Everything I found supported that conclusion. It was unanimous. Kirby even describes the amount of evidence supporting this conclusion as "overwhelming."

I was not able to find data specifically limited to the Pill, but part of that may be due to the fact that there are currently at least thirteen different contraceptive methods available, including three different formulations of the Pill. Most studies looked at contraception generally, one I found looked specifically at the effect of condoms on behavior, in the context of HIV prevention.

One thing that became clear is that access to contraception isn't enough. Access to information and education is also very important. Zabin found that access to a health clinic that sounds very similar to the one in Maine (access to sexual education, counseling, and access to contraception and medical services) actually resulted in a significant delay in the onset of sexual behavior. Quoting the study:

While the changes in the age at first intercourse are not large, they are substantial enough -- in the direction of delay -- to refute charges that access to such services as those provided by the program encourages early sexual activity... The project appears to demonstrate that if students in junior high schools are given access to nearby services and if they are offered information and continuity of care, they will use such services, and at levels comparable to those shown by older teenagers.

It usually takes about a year for an adolescent female to seek contraceptive services after the onset of sexual activity. (Committee) The Zabin study found that with one year's access to the program, a female student was about twice as likely to have sought out such services before becoming sexually active, and the percentage at six months was 70%. In other words, it is important that sexual education and contraceptive access start before the onset of sexual activity. The median age for this onset in the Zabin study was about 15. (Admittedly, this was a study in an urban high school, were it is likely to be younger than elsewhere.)

Guttmacher et al. did a study on the effect of the condom distribution program started in 1991 in all New York City schools. This was done in the context of HIV prevention, but their results should be relevant in this discussion of sexual activity as well. They found:

Clearly, making condoms available at school does not lead to increases in sexual activity.


higher-risk students reported getting a condom from school in significantly higher proportions than lower-risk students.

There was also some concern raised in the IP discussion about the confidentiality of these medical services. Several commenters felt that not informing parents that their children were sexually active was a violation of their "parental rights." According to the Committee report:

The primary reason adolescent's [sic] hesitate or delay obtaining family planning or contraceptive services is concern about confidentiality.

In other words, the best way to make sure teenagers do not use birth control or condoms is to tell their parents. I understand the concern here, but a parent's rights over an adolescent are not absolute. It is the moral and ethical duty of any health care worker to care for his patient's medical needs first; the abrogated rights of a third party are a secondary concern. This isn't to say they're unimportant, as in the case of mandatory reporting of rape or abuse, but a teenager above the age of consent has some medical privacy rights.

Conservatives have been pushing for abstinence-only sex education for some years now. There's even a new TV ad pushing parents to tell their children to not have sex. Personally, I think this is stupid. Not only does it completely ignore the existence of gays and lesbians, not only is it a practice that isn't used by 90% of the American population, and not only is it the only instance I know of where mandated ignorance is a form of education, but there's this to consider:

About 26% of adolescent couple trying to abstain from intercourse will become pregnant within 1 year. [Committee]

Conservatives usually inflate and distort condom failure rates when they try to claim they're ineffective, but they never cite the failure rate for their abstinence programs. Over one quarter of abstinent teenage couples get pregnant within a year, and that's not counting the couples that fail at abstinence and don't get pregnant!

Lastly, I just want to point this out to parents that still look down on sex education and contraception. This has got to be one of the most frightening statistics I've seen:

First intercourse was nonvoluntary for 9 percent of teen females. This percent was higher among those who were younger at first intercourse. (Abma)

If that doesn't make you think "Holy crap!", what does? I'm not quite sure if the use of the word "nonvoluntary" means some of these girls were just pressured into having sex as opposed to out-and-out rape, or if that's just scientific jargon for rape, but it's a stunning percentage. One in ten.

Mind you, that's just for first intercourse. One in four women will be raped in their lifetime. I can't find statistics that break it down any further, but women between 16 and 25 years old are at more than three times the risk of women in any other age group, and about 20% of women are raped by the time they're college-aged. It's sort of out of the scope of this blog post, but remember that women are not the only ones at risk. Six percent of rape victims are men, and in about 10 percent of both rape attempts and sexual assaults, men are the victims.


The literature conclusively states that access to contraception does not hasten the onset of sexual activity. Access to a comprehensive sex ed program as well as contraception actually seems to delay sexual activity in teenagers, if they get it early enough.


  • Abma, J. C., G. M. Martinez, W. D. Mosher, and B. S. Dawson. "Teenagers in the United States: Sexual Activity, Contraceptive Use, and Childbearing." Advance Data from Vital Health and Statistics. Series 23. Number 24 (2004).
  • American Academy of Pediatrics Committee on Adolescence. "Contraception and Adolescents." Pediatrics 104. 1161 (1999).
  • Guttmacher S., L. Lieberman, D. Ward, N. Freudenberg, A. Radosh, and D. Des Jarlais. "Condom Availability In New York City Public High Schools: Relationships to Condom Use and Sexual Behavior." American Journal of Public Health. 87. 1427. doi:10.1542/peds.104.5.1161 (1997).
  • Kirby, D. "Emerging Answers: Research Findings on Programs to Reduce Teen Pregnancy (Summary)." Washington, DC: National Campaign to Prevent Teen Pregnancy (2001).
  • Mosher, W. D., G. M. Martinez, A. Chandra, J. C. Abma, and S. J. Willson. "Use of Contraception and Use of Family Planning Services in the United States: 1982–2002." Advance Data from Vital Health and Statistics. No. 350 (2004).
  • Zabin, L. S., M. B. Hirsch, E. A. Smith, R. Streett, and J. B. Hardy. "Evaluation of a Pregnancy Prevention Program for Urban Teenagers." Family Planning Perspectives 18. 119 (1986).

Saturday, October 20, 2007

Is politics just tribalism?

Sorry to have not written anything in a while. I've just been swamped and for most of the past week my internet connection has been unpredictably up and down. Now that I've got a shiny new cable modem things should get better.

One of the things I've wanted to write about for a while is whether or not politics and our public discourse in general is just tribalism. By that I mean that people associate themselves with either Republicans or Democrats and have an emotional stake in that decision. After a while, it becomes about maintaining that identity and keeping power away from the other side, rather than thinking about the issues and trying to come up to the best solution to a problem.

Of course, as soon as I started thinking of this post, Dispatches from the Culture Wars said it better than I ever could. Here he's talking about a blog getting tagged as left or right:

...down with dualism. The whole point of such dichotomies is to avoid having to think. If you can just put that "liberal" or "conservative" label on someone, you can know whether to dismiss them or not. If you're intellectually lazy, that is. If you're capable of rational thinking, you know that labeling an argument does not defeat the argument and that you actually have to examine the logic of the argument and whether it explains the evidence or not.

And a couple of months ago:

I think that is the emotional root of why people respond so virulently to such [separation of church and state] cases, because in their mind religion is primarily a form of tribalism - those who agree with you are "Us" and those who don't are "Them." The moment you buck the majority, you are immediately placed in the "Them" category and the basic tribalism instinct kicks in; they truly do see themselves as protecting the in-group from the barbarian hordes at the door.

I've noticed this while hanging out over at Illinipundit. Commenters there are quick to start ridiculing their opponents as traitors, Marxists, socialists, anti-troop, illiterate, stupid (I'm looking at you, JB), and so forth. It quickly stops being about analyzing the issue or even trying to have a discussion, and becomes about attacking the ideological enemy.

In one of the debates, every single Republican Presidential candidate said that evolution was wrong. I really have a hard time believing that these presumably well-educated and reasonably smart guys, every one, thinks that biologists, cosmologists, and astrophysicists are wrong about their own field of study. It's the same thing when Bush said he would never appoint anyone to the Supreme Court that could approve of the Dred Scott decision. Come on, does he really think that there are a lot of Supreme-Court-quality lawyers that support slavery? No, this was a coded message about Roe. Both of these things were a way for the candidate to say to his followers, "Here I am. I'm one of you. I'm one of the tribe. Trust me."

Saturday, October 06, 2007

Third of a dozen

4 Jobs I’ve Held

  • Paperboy
  • Dishwasher
  • Engineer @ International Space Station
  • Postdoc
4 Films I Could Watch Over and Over
  • Hmm. I'm not a big fan of watching movies many times
4 TV Shows I Watch
  • Just 4?
  • Grey's Anatomy
  • America's Test Kitchen
  • Heroes
  • The Closer
4 Places I’ve Lived
  • Lawrenceville, NJ
  • Socorro, NM
  • Houston, TX
  • Champaign, IL
4 Favorite Foods
  • French fries
  • Chinese dumplings
  • Thai curry
  • Pizza
Oddly, I don't eat any of those too often 4 Websites I Visit Everyday
  • New York Times
  • Pharyngula
  • AmericaBlog
4 Favorite Colors
  • Blue
  • Purple
  • Green
  • Translucent
4 Places I Would Love to Be Right Now
  • Nowhere. I hate traveling.
4 Names I Love But Would/Could Not Use for my Children
  • Honestly, I've never given this any thought
4 Books I Could/Have Read Over and Over
  • Chronicles of Narnia, C. S. Lewis
  • Wheel of Time series, Robert Jordan
  • The Sandman series, Neil Gaiman
  • Memory, Sorrow, Thorn, Tad Williams
Pretty much everyone I know has done this so I can only tag: