Embryo grading, the scientific selection of the embryos most likely to succeed when implanted, is just one part of a fertility treatment. While you may find a fertility treatment in which you can opt out of grading, you can (and often should expect to) combine grading with any of the following:
In Vitro Fertilization (IVF)
Embryo grading is perhaps most commonly combined with in vitro fertilization (IVF), a fertility treatment in which an already-fertilized embryo is implanted into your uterus. You can elect not to have grading performed with IVF, but that will decrease your rate of success and is not typically recommended. When combined with IVF, grading will determine the highest quality embryos and a number of these embryos--anywhere from two to six--will be implanted to increase your chances of success. (However, the multiple embryo implantation is one of the reasons why IVF has a higher rate of multiple births than natural conception.)
Zygote Intrafallopian Tramsfer (ZIFT)
Zygote intrafallopian transfer (ZIFT), an alternative to IVF, can and often does make use of embryo grading, although may more be appropriately called "zygote grading" with this procedure. A zygote is a fertilized egg not quite formed into an embryo. However, your fertility specialist will grade the zygotes and select the two to six zygotes most likely to succeed for implantation, so the process is much the same.
Aside from the zygote/embryo difference, the primary difference between ZIFT and IVF is the place where the fertilized eggs are implanted; in ZIFT, they are implanted into one of your fallopian tubes instead of into your uterus. The fallopian tubes is where eggs are fertilized in a natural cycle, after which they will eventually fall into the uterus. Unlike IVF, during which the embryo is implanted via the vagina, ZIFT will require an incision in your abdomen.
Assisted hatching is an optional procedure most often combined with IVF, which is in turn most often combined with embryo grading. Assisted hatching takes place in the lab and involves your fertility specialist using a small, specialized tool to gently break up the outer layer of the embryo's shell, after which the embryo is immediately implanted. This procedure increases the success rate of IVF slightly, especially in women who are 37 or older and/or women who have tried fertility treatments such as IVF on their own unsuccessfully for at least a year. However, there are some caveats to the procedure because it's so delicate. It may slightly increase the child (or children's) chance of coming down with a developmental disorder, and it will also increase your chances of having identical multiples (and with a slightly greater risk of conjoined multiples).
Some people object to embryo grading because it boils down to scientific selection of some embryos over others, often resulting in the poorly graded embryos being discarded. Nevertheless, grading can significantly increase your chances of successfully becoming pregnant. If you're interested in the grading process or in finding an alternative that doesn't involve grading, discuss your options with your fertility specialist.