The French scientists in biology have gotten a setback with the dismissal of Lamarck assumption and theory of evolution by the use of function. Now, most of the French science in biology is trailing after the English and American one. You can see it when you open any book or site in biology written by a French biologist.

With the new discovery that stem cells can cross species barrier, some people may think that there can be a revival of the debate. However, stem cells even if they can bring a new function (a new phenotype) to a an organism in need (by their use in needed situation) does not bring any change in the genotype of the organism. Thus, the adage "La fonction par l'usage" ("Function comes by using the organ") cannot be verified in genetics and will have much difficulty to be accepted again in biology. Thus, the change brought by stem cells in an individual will not be inherited by its(his) descendants.

What is clear is that in the expression of a gene, something may be perturbated or regulated by the cytoplasm that could lead to a modified phenotype. Finally, while some mutations may be caused by the environnment, like in the case of rays, natural selection that implies the predominance of the most adapted, the most fitted species, the most competent genotype, is always the ultimate cause of the evolution. Environment is thus an indirect cause of evolution, it assures only the permanence of changes (genotypic-->phenotypic) that have happened mostly at random. That discards any thought to a return to Lamarckism.