The familial tendency of having twins, triplets, and multiples can have a genetic component. In your case, having a twin, and having aunts and cousins who have also had twins, triplets, and multiples suggests a possible genetic predisposition for multiple births in your family. This is often attributed to a higher frequency of a specific gene or genes associated with hyper ovulation, where more than one egg is released during a menstrual cycle, increasing the chances of multiple pregnancies. It's important to note that genetics plays a role, but it is not the sole determinant of multiple births as other factors such as maternal age, reproductive history, and assisted reproductive technologies can also influence the likelihood of having twins, triplets, or multiples.