Amazing and kind of cool–especially considering the two fetuses are only a couple weeks apart in age so they can safely be born at the same time inshaallah. 
This reminds me in a weird way of cats—when female cats are in heat they can ovulate multiple times over several days and often are ‘fertilized’ by multiple male cats. So in some litters of kittens not all the babies have the same dad or were conceived at the same time.