Abstract: The present invention relates to a method for the production and secretion into animal's semen of an exogenous recombinant protein comprising the steps of: a) producing a non-human transgenic animal characterized by an expression system comprising a promoter specific for the genital tract or accessory glands operatively linked to an exogenous DNA sequence coding for the recombinant protein through a DNA sequence coding for a signal peptide effective in secreting and maturing the recombinant protein in genital tract tissue; b) collecting semen produced by the non-human transgenic animal; and c) isolating the exogenous recombinant protein from the semen.