With either the Researcher start or the Microwaved feat you have more control over what infections, if any, you take. I always prefer to play pure human so I rush to collect 2 goo from the Goo girls at the mall, 2 gryphon milk from the blue gryphons right outside trevor labs, and then make sure I hit level 3 so I can just turn in the items for Doctor Matt's quest and wait until he's done. He gives you the option to volunteer for bonus feats every three levels, and completing his quest gives you the idea for Microwaves, unlocking it as an option when you volunteer for a feat.