The invention relates to a method for determining the sperm quality of vertebrate animals. Such a method comprises the following steps: Measuring at least one absorption spectrum of a sample of the sperm selecting a number n of wave numbers sj (j?[1n]) characteristic of sperm from the animals breed or species on the basis of said at least one absorption spectrum, determining a value for the absorption Xj and/or a value for the second derivative of the absorption Xj" (j?[1n]) for each of said n wave numbers sj (j?[1n] ) calculating a non-return rate Y at a predefined number of days from the previously determined values for absorption Xj and/or the second derivative of absorption Xj".
