Thats just people over reacting. Animal science is what I studied in college and the industry I worked in until very recently. There is no reason that it would be harder for you to get pregnant because you have dogs in your house. If anything people say animals relieve stress which would be a positive thing.
As for the crippled baby thing, dogs can carry a few parasites which can cause a range of problems but its VERY rare to catch this. It's just about good hygiene and keeping your dogs regularly wormed. It may sound obvious but it's more important than ever to make sure that nothing comes into contact with your mouth that has been in contact with your dog. That means thinking before you bit your nails (like I do) if you've touched the dog or not letting them get where you sleep or lay down like your bed or sofa because they have a habit of leaving behind an area of shedded hair and grit from their coats and with it possibly the parasites too.
I think the reason you hear more about cats is because it's believed dogs don't shed toxoplasmosis through their poop but cats do. Also cats tend to get everywhere to spred this, where as dogs only go where you let them. The biggest one in dogs is toxocariasis but there are others. It's just much more rare to catch it.
