My wife and I want a baby but I am infertile, would my brother's sperm be the same?

Although I am certain that the sperm would not necessarily be the same, the fact that they do possess some of the same genes would make it more possible to have a baby from a biological perspective. The resulting baby may not look exactly like you, but there is no doubt that he/she would possess traits similar to yours. Hope that helps!

From the biological perspective, you and your brothers' DNA can still be infinitely different despite being from the same parents, due to independent assortment of chromosomes as well as the different specific allelic sequences your specific egg and sperm had compared to your brothers. The only exception to this is if your brother was also your twin, and your identical twin not a fraternal twin.

That being said, there is a good chance many of your traits will not be apparent in your child if you decide to have your brother's sperm fertilize your wife's egg.

Your sperm would be more similar than that of a random person in the human population, but could still be wildly different. I wish I could expound further on why, but I'm pretty sure I slept through most of that class in high school. ;)

No it doesn't mean he is also infertile. The surest way to find out is to speak to him about being tested and tell him why. He may be your brother and love you to pieces but he may feel a bit weird about having a child but not being the one to raise it.You must admit the situation is just a little strange.

No, unless you are Identical Twins, your DNA is different, therefore it would not be the same.