Genetic Testing

The medical term for genetic testing is Preimplantaion Genetic Screening (PGS)  or Preimplantation Genetic Diagnosis (PGD). These are tests that look at the genetic viability of the embroy/blast before implantation, screening for conditions such as Downs Sydrome, since that is visible in the genes. Since the test looks at the blastocyst on a chromosomal level, the sex of the baby will be in plain sight. Some clinics will disclose that and even let you chose, some clinics have a strict policy against letting you know. (To this day, any tests associated with sex selection in Canada, are banned. Therefore, it is highly unlikely that your clinic in Canada would have this option.)

Knowing that your embroy/blast has a very high chance of being genetically viable, reduces the fear of losing the pregnancy due to genetic factors. It also reduces the need for transfereing multiple embryos, only to have to reduce one or more of them once they have implanted (which is difficult and controversial)

Here is more information on PGS:
http://en.wikipedia.org/wiki/Preimplantation_genetic_diagnosis

The type of PGS that our blastocyst underwent is called CCS (Comprehensive Chromosomal Screening)
http://www.colocrm.com/Services/ComprehensiveChromosomeScreening.aspx
This is how the procedure was explained to me: on Day 5 after fertilization, the blastocyst has specialized its cells into what will be the placenta and what will be the baby. Remember that the placenta is genetically your baby's organ, not yours. The cells that will be the placenta are on the outside of the blastocyst, and it is one of these cells that are "biopsied" away from the blast to undergo the testing. After the biopsy, the blastocyst is frozen because the results of the testing take around two weeks. Under the microscope, the chromosomes of the cells are analysed by arranging them in their 23 pairs. If there are an abnormal number of chromosomes (such as a third copy of chromosome 21 in Downs Syndrome) the blast is not viable and will not be transferred. If the 23 pairs of chromosomes are normal, then the blast will the thawed and transferred when the couple is ready to proceed. The CCS test, at the time it was performed, was 90% accurate.
Again, I cannot stress enough how much more relaxing and enjoyable my pregnancy was, knowing that I was carrying a genetically viable baby (with a minuscule chance of error, but that was not a concern). While everyone held their breath for the first 12 weeks for us, I would get annoyed and feel like I was dealing with prehistoric notions. Even when I explained to everyone what all that my baby underwent to be here, they still didn't get it, and continued to hold their breath. (Just a side line)
In any case, I recommend genetic testing prior to implantation, if it's possible where you are. The goal of IVF is to get pregnant and deliver a healthy baby. PGS makes that much more possible. Sex selection is not something I had experience with. That is your decision should you have the option.