Q1. A father who is the hemophiliac marries a woman who does not carry disease. While pregnant with their first child, an ultrasound reveals it will be a boy and the tech tells them that they are very lucky, since now they know their child will not be a hemophiliac! Explain how they know this.

Q2. It is because identical twins resulting from the similar fertilized egg (zygote) are actually the same individual. The entire DNA in all their cells is 100 percent identical. They are clones. Transplantation between two of them is equivalent to donating your own organs to yourself. Fraternal twins (from two separate zygotes) are not identical and are not the identical individual. They are though more closely related to each other than they are to either of their parents.