Identical twins same sex. This type of twinning could exhibit characteristics with reversed asymmetry, such as opposite dominant handedness, dental structure, or even organs situs inversus. Identical Twins Fraternal Twins. Regular weight-bearing exercise and maintaining a diet rich in calcium from childhood will help reduce bone loss at menopause Lay summary — "'Semi-identical' twins discovered" Nature News These babies will be no more alike than siblings born at separate times. Most conjoined twins are now evaluated for surgery to attempt to separate them into separate functional bodies. This differs from fraternal twins, where two eggs ova are fertilised by two sperm and produce two genetically unique children, who are no more alike than individual siblings born at different times. If this blastomere then undergoes a twinning event, two embryos will be formed, with different paternal genes and identical maternal genes. There are different types of breast cancer, and around 70 per cent are sensitive to the female sex hormone oestrogen Skip to main content. These babies will be no more alike than siblings born at separate times.