I don't have a knee-jerk reaction to remakes. As I'm fond of telling people, the Bogart/Huston version of The Maltese Falcon is the third screen version of that story within a ten year period. Sometimes it takes a couple of tries to get it right. Which, by the way, is why filmmakers are better off rethinking bad movies rather than classics. Of course, this line of thinking presupposes that the remake improves on the original. The nature of contemporary remakes means that the actual quality of the movie is an afterthought.
Here's the thing about Larry Cohen's original version of It's Alive: it's ridiculous. It's a film that attempts to exploit the unease that pregnancy generates for new parents. It exploits the fear that something is wrong with a newborn child. It's the product of the thalidomide tragedy. The method it uses to examine this unease is a mutant killer baby. This is it: