Abigail Loraine "Abby" Hensel and Brittany Lee Hensel (born March 7, 1990) are dicephalic parapagus twins, meaning that they are conjoined twins, each of whom has a separate head, but whose bodies are joined. They are highly symmetric for conjoined twins, giving the appearance of having just a single body without marked variation from normal proportion. In fact, several vital organs are doubled up; each twin has a separate heart, stomach, spine, lungs, and spinal cord.
In conversation, the twins are clearly distinct persons, with distinct likes and dislikes. Their preferences in food, clothing color, etc., differ. Some of their clothes are altered by their seamstress so that they have two separate necklines in order to emphasize their individuality. They will usually have separate meals, but sometimes will share a single meal for the sake of convenience (e.g. each taking a bite of the same hamburger). Abby is better at mathematics, and Brittany is better at writing. For tasks such as responding to email, they type and respond as one, anticipating each other's feelings with little verbal communication between them.