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.
Updated December 01, 2016. Having a baby boy is something that is important to some parents â enough so that they try to influence their pregnancy and become pregnant with a boy, through a variety of means. This is called sex selection and can be done for boys or girls.