The use of indirect selection criteria together with the classic criteria has been proposed to increase the selection scheme efficiency. This use supposes knowing the genetic parameters and particularly the genetic correlations between criteria. The failure of genetic improvement of the female reproductive traits through the testis measurements of their related males illustrates the difficulties of indirect selection, even in case of favorable genetic parameters. Moreover, the difficulties found to combine two criteria that compose litter size in a better index that the one provided by the classic criterion, show that linear combinations of several criteria can have sometimes a low selection efficiency. The recent changes of the biology provide to the breeder a large amount of new criteria which are of two types. On one hand, there are now in all the species a large number of QTL markers (microsatellites or SNP). Nevertheless, except for very specific cases, these markers present more interest for gene localisation or identification than as criteria to integrate in a selection process. On the other hand, several causal mutations have been discovered; they present in some cases a great interest for the genetic improvement but their integration in genetic evaluation is scarce. Without any doubt methodological developments are still necessary to combine elementary selection criteria in more effective indexes.