Ericsson method
The Ericsson Method is a child conception idea that is reputed to help determine a baby's sex, developed and patented by Dr. Ronald Ericsson. The method has been in use since the mid-1970s. Dr. Ericsson maintains that the method is up to 85 percent effective, but some experts question the effectiveness of the method.
Experiments with the Ericsson method have determined that the method does not create X- or Y-enriched sperm samples. Nevertheless, some studies have suggested that, at least with parents seeking girls, a 71 percent success rate can be obtained.
The Ericsson method is based on the belief that X-sperm swim slower than Y-sperm. Sperm are placed in an atop a "column" of increasingly thicker layers of albumin, and allowed to swim down into the solution. After a certain time period has elapsed, the sperm can be separated into the faster and slower swimmers. If the couple desires a male baby the faster swimmers are artificially inseminated, and if the couple desires a female baby the same procedure is enacted with the slower swimmers.