1. becoming a member of a social group will half your probability of dying in the next 12 months. this is roughly equivalent to the effect of smoking. so, if 1) you smoke, and 2) you have no friends, these two are equally dangerous to your health.
2. cells replicate themselves by creating two copies that go on to create two new cells each. human cells can regenerate themselves about 50 times before the process stops. by the time this finishes happening (after 50 generations) the “descendents” of a single cell could cover an area roughly equivalent to manhattan. (listen to the “mortality” episode of radiolab for more info on this.)
3. vaccines are incubated in cells that are grown in human cells that have been regenerated in a lab. in the 1950’s the source of these human cells was aborted fetuses. everyone that hase been vaccinated against smallpox, polio and a number of other diseases (totalling about 1,000,000,000 persons) has been vaccinated with viruses that were incubated in the cells of a single fetus aborted by a swedish woman living in the usa. (listen to the “mortality” episode of radiolab for more info on this.)
4. while it is illegal to sell human organs for transplantation in the usa, it is not illegal to sell human tissue (such as bone, tendons and skin). the american tissue donation industry is a $1,000,000,000 a year business. (link)