The geneticians who have studied the boys’ case, believe that they could be the offspring of four different fathers, a phenomenon called heteropaternal superfecundation. Fraternal (dizygotic) twins are the result of hyper ovulation, which means the release of multiple eggs in a single cycle. Superfecundation describes a situation where the eggs are fertilized by sperm from separate incidences of sexual intercourse. In a case where a woman has sex with different partners, the twins could have different fathers.
In another case well documented case of multicolored twins, one parent was white and one was black, and – as can happen with any fraternal twins – Lauren took after her mother, Alison Spooner, while Hayleigh took after her father, Dean Durrant. What makes this family so remarkable is that this happened not once but twice, seven years apart. British researchers calculated that the odds of two sets of “black and white twins” in the same family are about 2 in a million.