Brendan wrote: Have you heard of Mexico and South America?

Yes.  What is the data?

Lets stick with the United States.  It is hard enough to control outside factors here, much less other places and cultures.

Latino people are overwhelmingly Catholic. Here's information about Latina women in the US:

http://www.prcdc.org/summaries/latinapreg/latinapreg.html

And more about our neighbors to the South:

http://www.overpopulation.org/culture.html#SouthAmerica

They are also poorer on average-so you'd have to account for that.  Attend crummier schools, on average.

Plus from the site:

Although the overall U.S. teen birth rate decreased 20 percent in the 1990s, it only decreased 12.5 percent for Latinas. Black, non-Hispanic teenagers had the greatest decline at 38 percent. Although black teens are more likely than Latinas to become pregnant, they are also more likely to have an abortion, which accounts for their lower birth rate.

In 1997, the Latina teen pregnancy rate was 165 pregnancies per 1,000 teenage women, a rate significantly higher than the national average of 97 but lower than the pregnancy rate of 179 for black teens.

I'd say that is a bit of a cheat in a decline of teen births, since the black teens (unlikely to be Catholic) who got abortions were pregnant at some point

Some other relevant differences, probably related to culture:

The proportion of teen births that are unintended varies significantly by race and ethnicity. In the 1990s, only 46 percent of Latina teen mothers reported that the birth was unintended, compared to 67 percent of white teens and 75 percent of black teens.

Latino teens report higher rates of sexual activity and lower-than-average rates of contraceptive use. In 1995, 56 percent of Latina females and 61 percent of Latino males reported ever having had sexual intercourse compared with national figures of 51 percent for teenage females and 56 percent for teenage males. Only 29 percent of Latino teenagers reported always using condoms in the past year compared with the national average of 44 percent.

Among teen mothers, almost 32 percent of Latinas are currently married, compared with less than five percent of blacks and 41 percent of whites.

Teen mothers are more likely than mothers who have their first birth in their twenties or thirties to come from poor or low-income families, live in poverty and depend on welfare. Overall, about 15 percent of all teen mothers receive welfare payments, compared to 26 percent of Puerto Rican teen mothers receiving payments. Other Latino groups are less likely to receive welfare, in part because of the large proportion of immigrants who are not eligible to receive it

So the Catholicism thing-there's too many other factors.  More of these girls want to be moms, got married young, came from poor families.

Sticking with the United States, I found an article about a study that showed Hispanic immigrants become more sexually active once they become immersed in American culture:

Link

Article may require log in, so here is an excerpt

QUOTE: As Hispanic teens shed the language of their native countries and immerse themselves in American culture, they become dramatically more sexually active, a new study shows. *** The study, published in this month's Archives of Pediatrics & Adolescent Medicine, adds evidence to the so-called healthy immigrant paradox, that Hispanics coming to the United States are healthier than second- and third-generation U.S. residents from the same countries.

The article does not discuss birthrates, but seems to conclude that stripping away the family-oriented traditional Mexican culture, and adding America's permissive attitude, but without promotion of birth control, is harmful.

It's like we are currently living in the worst of both worlds in the U.S.A.  We have the glorification of recreational sex, but without the comcomitant emphasis on birth control.  You kind of have to go one way or the other.  But there are those us who think "the other" is  best.

I will agree that it's not a 100% cause-and-effect issue, but I can tell you from personal experience (this one and others) that the Catholic ban on birth control has been a factor in many unplanned pregnancies.
*****

Also from personal experience, I can tell you that the Catholic ban on birth control has NOT been a factor in the lives of many Catholic and their perosnal choice of controception.

Sheesh, Joe and Rob, did I say that the Catholic position on birth control means than no Catholics use birth control? I am aware that many Catholics ignore the parts of the church's teachings to serve their own purposes. That's one of many reasons I don't have much use for organized religion.

Your argument seems to suggest that the taboo subject of birth control in Catholic families has never been a factor in an unplanned pregnancy. I know for a fact that this is not the case. If that's not what you are arguing, what are you trying to say?