What is the term for twins that are not identical and share approximately 50% of their genes?

The term for twins that are not identical and share approximately 50% of their genes is dizygotic twins. These twins are formed when two separate eggs are fertilized by two separate sperm cells during the same pregnancy, leading to the development of two genetically unique individuals. Since they originate from different fertilized eggs, they possess a genetic similarity akin to that of regular siblings, which is about 50%.

Dizygotic twins can be of the same sex or different sexes and are often referred to as fraternal twins, which is a term that is commonly used interchangeably with dizygotic twins. However, the more specific genetic designation is dizygotic, emphasizing their origin from different zygotes.

Monozygotic twins arise from a single fertilized egg that splits into two embryos, resulting in genetically identical individuals. Same-sex twins is not a formal classification in this context, as it simply describes the sex of the twins and does not denote their genetic relationship.