Pregnancy rate after ART (Artificial Reproductive Technology) is abusively considered to increase in proportion of the number of embryos transferred. Indeed this is only true up to less than 5 embryos, and is highly dependant on the woman’s age. Above all a policy of too many embryos transfer entails an excessively high number of multiple pregnancy, as high as 26-30%, including 3- 4% triplets. The hazards of multiple pregnancy both for mothers and offspring led several countries to limit by law the number of embryos to be created/transferred during ART. A policy of a single embryo transfer, eventually followed, in case of implantation failure, by the transfer of a cryopreserved embryo during a next cycle, has proven to be significantly as efficient as the transfer of two fresh embryos, with a drastic reduction in multiple pregnancy. The advantage of the transfer of a single embryo at the blastocyst stage is discussed. FIGO Ethics Committee recommends an embryo policy transfer achieving a singleton pregnancy.