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.
XX or XY Odds. Are the odds of having a boy or girl really 50% each time? What if you already have one boy or 2 or 3 boys? Is it really a 50% chance that you will have a girl next? Letâs look at the odds of having a boy or a girl, given that previous children are all of the opposite gender. Odds of Having a Girl.