Nutguy

I'm quite new at the game (I'm actually playing it for the first time odd as it may seem) and have encountered some problems regerding the research tree. The research topic I can't get into is the "Alien life cycle". Now, I 've seen at a site that the prerequisites for it are the "Multiworm", "Multiworm Autopsy", "Multiworm Egg", "Multiworm Egg Autopsy", "Chrysalis", "Chrysalis Autopsy". The problem is that I've already researched all of these and it doesn't show up. First of all, are the prerequisites correct or am I wasting my time here? Secondly, does the fact that I researched "The Alien Genetic Structure" after all of these have anything to do with it? And last, but not least, can I get to "The Real Alien Threat" (and the much needed Toxin C it enables) without the life cycle? Thanx in advance...