Here is some important info from the US that we missed last week. A report from the federal health monitoring agency, the Centres for Disease Control and Prevention (CDC), brings the news that births to teenagers aged 15-19 are down by 44 per cent on 1990. The 2010 birth rate for that age group of 34.3 per 1000 females represents a 70-year low, and record lows for all racial/ethnic groups.

Actually, by itself a lower teenage birth-rate is an equivocal statistic. It could have been brought down by abortion. It could mean that hundreds of thousands of young women are on hormonal contraceptives that make them vulnerable to diseases and facilitate harmful relationships. It is a matter for ethical evaluation whether it is worse for an 18- or 19-year-old to have a baby than to be subject to these alternatives.

The good news is that the dramatic drop in pregnancies is related first and foremost to increased sexual abstinence among teens. Those reporting (in the National Survey of Family Growth) that they had never had sexual intercourse increased from 48.9 per cent in 1995 to 56.7 per cent in 2006-2010 - a 16 per cent change. Significantly, this increase was greater among 18- to 19-year-olds (from 28.9 per cent to 36.5 per cent, which = 26 per cent increase) than among 15- to 17-year olds (from 61.4 per cent to 72.9 per cent = 19 per cent).

That suggests at least three-quarters of high school teens have never had vaginal sex, and more than a third of those starting college. Well over half of the combined age-groups say they have never had sex. You can believe them or not, but there is no evidence to support a statement like, “Most American teens have had sex by the time they leave high school.”

It is true that the CDC report shows contraceptive use has risen -- yes, it has and you can read the details in the report. But the report expressly puts abstinence first as a cause of the trend:

Declines since 1995 likely reflect significant increases in the proportion of female teens who were abstinent, and among sexually experienced female teens, increases in the proportion using highly effective contraception (5).

And it says this is the way to continue reducing what is still a high unwed teenage birthrate by developed world standards:

Addressing the complex issue of teen childbearing requires a comprehensive approach to sexual and reproductive health that includes continued promotion of delayed sexual debut and increased use of highly effective contraception among sexually experienced teens.

Report author Crystal Pirtle Tyler, a CDC health scientist, told one health news site:

To keep teen pregnancy rates declining, teens and their doctors need to have talks about delaying having sex, Tyler said. "It would be great if teens know that the majority of teens have never had sex," she added.

Even teens who are sexually active can be counseled to stop having sex, Tyler noted.

A particularly positive sign is that abstinence has increased more among Black teens than among Hispanics and whites. Black teens reporting they had never had sex rose from 40 per cent in 1995 to 53.6 per cent in 2006-2010 -- a 34 per cent increase.

The CDC would like to see more sexually active teens using “highly effective” methods of contraception, in particular long-acting methods such as IUDs and implants, together with condoms for disease protection. But the report notes how difficult it is to get kids to use condoms properly:

Condoms, the method used by many teens, can provide effective protection against unintended pregnancy when used consistently and correctly; however, during 2006–2010, only about half (49%) of female teens who used a condom for contraception reported consistent use in the past month (6).

Do they really think they will ever win this battle?

Anyway, over all, good news.