THE film Six Degrees of Separation describes a 鈥渟mall-world network鈥�
where everyone in the world can be linked to everyone else through, at most, six
others. Now scientists have found that the number of 鈥渟exual links鈥� needed to
connect two people could be even fewer.
Luis Amaral at Boston University and colleagues at Stockholm University
analysed data from a sex survey of 2810 Swedes (Nature, vol 411, p 907). By
checking how many sexual partners people had in one year, they could estimate
the number of amorous links needed to connect two people.
鈥淎ny two people might only be two or three connections apart,鈥� says Amaral.
The reason, he says, is that some people had a very high number of sexual
partners. Targeting these people could make health campaigns more efficient, he
adds.
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