The older that such fish become, the more mercury they may have absorbed. Anything that eats these fish within the food chain also consumes the higher level of mercury that the fish have accumulated. This process explains why predatory fish such as swordfish and sharks or birds like osprey and eagles have higher
The goal, then, when it comes to having a boy is to increase the likelihood that a Y chromosome sperm reaches the egg first. Many medical researchers believe that Y chromosome sperm are faster swimmers, but that X chromosome sperm have more endurance.
Taking fertility drugs is linked to a greater chance of conceiving two or more babies, and carrying multiples is considered a high-risk pregnancy. If you use a fertility drug (such as clomiphene citrate) to induce ovulation before IUI, your chance of having twins is about 10 percent.