http://www.imagineyh.com/html/features/infertility/article/article_nov00_1.php3
Hey Maureen, i'm just as confused as you are... i was quite surprised to read Dr. Potter even mentioning Gradient Selection in the interview...but apparently it gets better PG rates than MS/IUI. I have asked Dr. Potter many times to clarify this for the past several weeks and still no reply from him... it IS confusing and if what he says is true about gradient selection having a 70-75% success rate then it should be promoted instead of Microsort for people who want boys since the stats are the same for both methods.
"The problem with Microsort, in my experience, has been that the specimens are so depleted that only several hundred thousand sperm are being inseminated at a time, says Dr. Daniel A. Potter, of the Huntington Reproductive Center. "So the pregnancy rates are very low." The pregnancy rate is 16 percent, below the natural conception rate.
Dr. Potter employs the other method: gradient selection. "It is based on a simple physics equation: force equals mass times acceleration."
....gradient selection is often a more attractive option to prospective parents because it is cheaper, performed in various clinics around the country, and the rate of successful insemination is higher than Microsoft's. The reason: the gradient method is easier on the sperm. Dr. Potter explains, "We will lose about half of the sperm when we do the procedure, but we will concentrate the sperm we do have and deposit them high up in the uterine cavity. So the pregnancy rate turns out to be as high as if the couple were having intercourse that month, that is to say about 20% per attempt." According to Dr. Potter, gradient selection is highly effective in selecting the sex of a child. "The success rate is about 70 to 75 percent. It is a little higher in girls."