The study described in the present paper attempted to clarify further the genetic and environmental etiology of schizotypal personality traits through biometric model fitting of data from a sample of MZ (n=91 twin pairs) and DZ (n=87 twin pairs) adolescent twins (age 11-13 years old) drawn from the general population. Univariate genetic analyses found that schizotypal traits are modestly heritable (additive genetic effects ranging from 35 to 49%). Multivariate genetic model fitting results indicated that additive genetic and unique environmental influences acted through a single common latent pathway for cognitive-perceptual, interpersonal-affective and disorganization symptom dimensions of schizotypal personality. The covariation among the three schizotypy sub-factors could be accounted for by a common 'schizotypy' latent factor which was significantly heritable, with additive genetic factors explaining 60% of the latent factor variance.