I've been soldering now for around 45 years, and I used to do a lot of bullet casting so I've handled a *lot* of lead in my time. I was taken ill a few years ago with some symptons that could be remotely explained by heavy metal poisoning so I was thoroughly tested. My lead levels were right on the average for someone living in an urban environment. So if you're sensible I don't see a problem. Don't eat sandwiches while you're soldering...and wash your hands when you're done ;-) Lead in gasoline (petrol over here) was a bigger problem.

Resin flux is a known carcinogen, so don't breathe the fumes.