Viaspace Giant King Grass shows high yield at California site. Viaspace Inc. has announced that the first harvest of Giant King Grass in the Imperial Valley of California, was completed on Sept. 2. At the University of California site in Holtville, California, two planting methods were compared.
Identical Twins occur when a single egg is fertilized by a single sperm to form one zygote (monozygotic) but the zygote then divides into two separate embryos. The biological mechanisms that prompt the single fertilized egg to split in two remain a mystery. The two embryos develop into foetuses sharing the same womb.
Here are the different combinations: 1  Fraternal twins could be produced when eggs from one woman are fertilized by sperm from two different men. 2  A woman may carry twins conceived in-vitro with donor eggs, which could come from two different women. 3  Donor eggs from two different women could be fertilized by sperm from two different men. In this case, the twins may have no shared DNA unless the sperm and egg donors were related. They would be similar to step-siblings. A Word From Verywell. You are likely to have to answer the same questions about your twins repeatedly.