[Lack of biological exchange in assisted reproductive techniques].

There is a clear dividing line in the group of actions aimed at solving sterility, and the techniques aimed at generating embryos to be transferred to a womb. The dividing line is now clearly established by science. The growing alarm among paediatricians raised by the higher risk of malformations and diseases in children when generated in vitro, with respect to those normally engendered, is leading to the need to clearly establish the consequences of in vitro technologies and informing society in an honest way. Two types of lack of exchange of information, cellular and molecular, cause the detected defects. In the fi rst place it is clear that both gametes should recognize each other when adequately mature and in the appropriate natural environment. In vitro technologies force these conditions and either one or both gametes might be impaired and consequently negative effects for the child might be caused. In the second place both embryo and maternal womb are deprived of that early mother-child communication facilitating implantation.