What is the difference between fraternal twins and paternal twins? What similarities do they share?

There is no difference between brothers and twins of fathers. Two words, same meaning. There is no difference, so there is no similarity. Paternal (brothers twins) are two eggs from a mother fertilized by two sperm cells from their father. (There are few sperm cells from two different fathers.) These twins occur in the amniotic sac that separates the mother's abdomen. These twins are the same as ordinary brothers and sisters. Another type of twin is caused by the egg division of the mother after fertilization. Each half of the division grows into an independent human with the same genetic structure. The same twins are in the same amniotic sac. These twin lives are exactly the same, but environmental factors may lead to changes that may become obvious in the future.

Twin studies involve analysis of the differences between the same twin and sibling twins. Since the same twins share 100% of the same gene and brothers twins occupy only 50% of the same gene, the same twins should be more similar than sibling twins if there are genetic elements in personality traits . Adoption studies involve analyzing the similarity between biological and adoptive relationships. When there is a genetic component in personality traits, adopted children are more similar to adoptive parents than their biological parents. Family studies, twin studies and adoption studies did not tell researchers what genes are involved. Instead, they show the effect of all genes on specific traits.

There is no difference between brothers and twins of fathers. Two words, same meaning. There is no difference, so there is no similarity. Paternal (brothers twins) are two eggs from a mother fertilized by two sperm cells from their father. (Twin sperm cells do not come from two different fathers.) These twins occur in the amniotic sac that separates the mother's abdomen. These twins are the same as ordinary brothers and sisters. Another type of twin is caused by the egg division of the mother after fertilization. Each half of the division grows into an independent human with the same genetic structure. The same twins are in the same amniotic sac. These twin lives are exactly the same, but environmental factors may lead to changes that may become obvious in the future.