Genetic markers will help doctors find the best embryos to increase the success rate of in vitro fertilization (IVF) in just one procedure. However, the disadvantage of IVF is that if only one embryo is placed in the uterus, the doctor has no criteria to choose a healthy embryo and one that is free of genetic diseases. This has changed when doctors can now biopsy "embryo cells for DNA testing to provide information about the ability of this embryo to become a fetus."