Two cigarettes a day does harm. Yes, it's a sliding scale and a fifty a day habit is worse than a two a day one, but it' sevruga dangerous to class yourself as a non smoker if you just have one or two a day. One cigarette a week does harm. I hate to be all doom and gloom about it but if you're smoking one or two a day you're still getting the negative effects of elevated blood carbon monoxide along with all the various substances in fags.
I actually think the nhs guidelines on booze are sensible. They are informed by the data we currently have, which is that there are various developmental windows where alcohol is more harmful.
The real problem (as with so many things) is that different bodies react differently to alcohol (and cigarettes)
If you have one copy of the alcohol dehydrogenase gene for example, you're going to metabolise alcohol much more slowly. Couple that with the fact that people vastly underestimate intake - that small glass probably isn't a small glass. 80ml of wine is roughly a unit, when did any of us last see that in a pub?
So the guidelines work on a population level, but your own personal reaction is unlikely to be that of the population average.
I really dislike this move to turn women into passive baby vessels. Give us the data, explain it very clearly, in plain English and let us decide.