The etiology of human same-sex romantic attraction is generally framed in terms of (1) social influences, (2) genetic influences, or (3) hormonal influences. In this article, we show that adolescent males who are opposite-sex twins are twice as likely as expected to report same-sex attraction; and that the pattern of concordance (similarity across pairs) of same-sex preference for sibling pairs...

Computational methods for discovering the preferences of individuals are useful in many applications. In this paper, we propose a method for learning valued preference structures, using a natural extension of so-called pairwise classification. A valued preference structure can then be used in order to induce a ranking, that is a linear ordering of a given set of alternatives. This step is reali...