Fake science

Usually I'm OK with fake science in science fiction and fantasy books. If they only used real science, they would not be sci-fi or fantasy, obviously. However, I was recently thinking about the fake science found in the Twilight books.
Brief background for those who don't know: There is a vampire, Alice, who can see the future of humans and vampires, but as soon as a werewolf is involved, the entire future disappears. In the final book (*spoilers*) she also can't see the future when Bella and Edward's half-human, half-vampire baby, whose name is Renesmee, is involved. It turns out that this is because humans have 23 pairs of chromosomes, vampires have 25, and werewolves and Renesmee have 24.
Where shall we start? First of all, when two species have a different number of chromosomes they cannot interbreed and produce offspring. Second, ignoring this, Renesmee would not have 24 pairs of chromosomes. She would have 23 pairs of chromosomes and two unpaired chromosomes. As you might expect, individuals with unpaired chromosomes suffer from a variety of unpleasant conditions, most frequently including physical and mental development issues and abnormalities. OK, now let us assume that somehow Renesmee's unpaired chromosomes chose to pair together and this did not cause vast problems for her.
Alice can't see species that have 24 pairs of chromosomes, or any events these species are involved in? This means she shouldn't be able to see the future any time cultivated tobacco, potatoes, hares, gorillas, chimpanzees, deer mice, orangutans or rhesus monkeys are involved. She had better avoid Africa.