Honey, I genetically engineered the kids. Adrien Brody and Sarah Polley in ‘Splice’.Better living through genetic engineering takes a serious hit in Vincenzo Natali’s Splice, a seriously creepy and surprisingly effective science-gone-awry thriller. There’s a certain 50’s B-movie sensibility going on here: where films like Godzilla or Them! expressed a public’s fears about the dangers of radiation, creating mutated monsters that threaten to bring down humanity, Natali’s film does the same with gene-splicing. Here,…