Every time a cell divides (as you grow, for example), a perfect copy of its genes is made. Just occasionally, this copying goes slightly wrong in which mutations or gene shuffling, called recombination, happens. It is these 'mistakes' which allow evolution to happen by trial and error. But genetic engineers deliberately insert new genes by recombination although they cannot tell where on the chromosome the genes they add will end up. So the process is random and may alter the way the new organism's genes behave in a way no-one can predict. This is one of the main reasons some people are worried about genetic engineering (GE). These transgenic organisms are, like Dr Frankenstein's monster, in a sense 'bolted together' out of bits of others. This is why GE foods have been called 'Frankenfoods' by protest groups — rather absurdly since millions of people have been eating them for many years now without any evidence of harm.
Did you know that the monster in the Frankenstein story ends up killing his creator's loved ones. And did you know that the original Frankenstein appears in a classic horror story published in England by the rather visionary Mary Shelley way back in 1818?