Summary: U
nlike clearly defined `real-world' net-
works1
, social networks tend to be
subjective to some extent2,3
because
the perception of what constitutes a social
link may differ between individuals. One
unambiguous type of connection, however,
is sexual contact, and here we analyse the
sexual behaviour of a random sample of
individuals4
to reveal the mathematical fea-
tures of a sexual-contact network. We find
that the cumulative distribution of the
number of different sexual partners in one
year decays as a scale-free power law that
has a similar exponent for males and
females. The scale-free nature of the web of
human sexual contacts indicates that strat-

Source: Amaral, Luis A.N. - Department of Chemical and Biological Engineering, Northwestern University
Stanley, H. Eugene - Department of Physics, Boston University

Collections: Biology and Medicine; Computer Technologies and Information Sciences; Materials Science; Physics