Caffeine's an interesting one. I'm doing my best to avoid it (although, I also cannot give up chocolate altogether), but, my doctor says that it's okay to have 2 servings per day. I looked up the research because I wanted to understand it better. They have proven that caffeine definitely crosses the placental barrier (meaning that if you consume it so does your baby) but a study in Europe showed that 3 cups of coffee a day did not affect rates of birth defects. But, they've really only looked at birth--there's no conclusive evidence that caffeine doesn't have later implications. There are also studies that have shown that caffeine can disrupt brain development in children until about the age of 16. So, I figure I'd rather avoid it.

As for the smoking issue--congratulations on trying to stop. I know that it is tough. Our clinic said that it was important to quit smoking at least 4 months before beginning TTC. I know that they were mostly concerned with sperm quality, so, it may not matter for you. But, you may want to check out whether you should wait an extra month or two after quitting.