[TigerXero]

Having two sperm fertilize one egg is a BIG no-no. The zygote (egg+sperm/single cell) would have too many chromosomes, hence why as soon as a sperm enters an egg, the egg cell's membrane undergoes a chemical change that prevents any other sperm from entering. If your question was about having two sperm cells fertilize an egg, then that's a problem in and of itself.

Otherwise... if you are talking about combining two XY DNA strands, then...
The only way I could think of to combine two male sperm cell's genetic information is to have some computer analyze two persons' DNA, calcluate what a joining of those two would look like, then artificially create that DNA strand, have it go through the process of meiosis, somehow put it in a sperm cell, and THEN allow it to fertilize an egg. OR, you could analyze two people's sperm cells (whose DNA have already undergone meiosis) and repeat the above process minus meiosis. Either way, both of these would require a lot of money, or some really good connections with someone in a genetics lab, but I don't even know if any of this is currently possible. It would work in theory though.

Yay~ for high school Biology II!