EN
The aim of this article is to present certain problems concerning construction and estimation of the family design models used in the behavior genetics research. As there are only two Polish examples of empirical research applying family studies method, we discuss main methodological and statistical problems regarding the models presented in these works, including certain doubts of ours considering construction and assumptions made. In the above mentioned articles their Authors use path model to describe connections between latent variables: genetic (G), common environment (C) and specific environment (E) and the observed phenotype variables. In this article we discuss the problem of particular parameters' constancy, relationship (or its lack) between particular variables, as well as problems of adequate estimation method, inferences based upon the constructed models and the application of given statistical methods used draw a conclusions on the models' fit.