lifelines : Mother knows best http://helix.nature.com/nsu/000907/000907-3.html

HELEN GAVAGHAN

Early sexual activity among teenagers and the associated risks of pregnancy and sexually transmitted disease is a growing problem in many parts of the world. Now research reported in the August issue of The Archives of Pediatrics and Adolescent Medicine1 indicates that if mothers clearly state their disapproval of sexual activity, in a warm and loving environment, adolescents are more likely to delay their first experience of sexual intercourse.

The factors influencing teenage sexual behaviour are complex and notoriously difficult to reduce to generalizations. Rennee Sieving, of the University of Minnesota in Minneapolis, and her colleagues have attempted to disentangle the impact of two factors on teen sexual activity: the perception by an adolescent of his/her mother's attitude, and the degree of closeness between child and mother.

Unlike most other studies, Sieving and her colleagues examined how accurately these two factors predicted future behaviour. Such prospective studies are rare, and more are needed, says Linda Blair, a clinical psychologist whose practice includes treating students at the University of Bath, UK.

In a sample of 3,322 teenagers, Sieving's team found that those who think that their mothers strongly disapprove of early sexual intercourse have sex later than others in their peer group. Unsurprisingly the researchers also found that a teenager's perception of his/her mother's opinions is more accurate when they report a "high degree of closeness".

Interestingly, teenagers whose mothers strongly disapproved of sexual intercourse perceived that disapproval to be less strong if their mothers talked about a specific form of birth control. This small but clear effect of talking about birth control methods should be investigated further, Sieving's group suggests. General discussions about sexual activity and contraception did not seem to affect the teenager's perception of attitudes in any way.

The sample of 3,322 was a subset of 12,105 students from high schools across the US who participated in a major study of adolescent health funded by US government agencies. Funding bodies included the National Institutes of Health, in Bethesda, Maryland and the Centers for Disease Control and Prevention in Atlanta, Georgia.

All 12,105 teenagers were interviewed twice: first in 1995 and then 10 to 18 months later. They were asked about family relationships, perceptions of parental attitudes and about their views on sex, alcohol, cigarettes, drugs and criminal activity. For sensitive topics, participants listened to questions through earphones and entered responses into a laptop. Parents were interviewed separately.

Sieving's group analysed this publicly available data, focusing on students aged between 14 and 17 who said they were virgins at the time of the first interview.

The team's results agreed with the predictions of a computer model based on a sociological theory -- the 'Theory of Triadic Influence' -- about the interaction between social, attitudinal and interpersonal factors. The model assigns numeric values to attitudes. For example, on a scale of 3 to 22, the 14 year olds and 17 year olds reported degrees of closeness averaging 19.5 and 19.4, respectively.

Blair cautions that sex drive and birth order are strong confounding factors. "Sex drive can be very strong and override perception of approval and desire to please a parent. I'm not sure you can generalize too much from this finding."

1.R. E. Seiving, C. S. McNeely & R. W. Blum. Maternal Expectations, Mother-Child Connectedness, and Adolescent Sexual Debut. Archives of Pediatrics & Adolescent Medicine 154, (2000).

© Macmillan Magazines Ltd 2000 - NATURE NEWS SERVICE