How small can the human population be in order to create a new line of healthy human beings?

Humans started out as really primitive creatures who lived in small groups consisting of hunters and gatherers. Most of the "cavemen" had to of been inbred to grow in population. Though some small groups might have become "civil" with one another most have faught. So if you really follow your family tree that far back your ancestors had to of been involved in some sort of inbred activity.Plus being inbred doesn't automatically mean there is something wrong with you. It just means there is a greater chance there was a mutation in your DNA.

Most of the time people don't make their offspring unhealthy, their lifestyles and the environmental factors around them do.
It's too late to be considering the effects of inbreeding, and is a bit difficult to avoid... If you spent a lot of time on it, you'd realize that everyone is related to everyone in SOME way many years ago, or not.

This question really can't be answered without more parameters involved - i.e. you need to define for how long, what sort of selection pressures are involved, and how related and diverse the initial population is.

See: minimum viable population

To give you an idea of how long inbreeding can last Line 1 Hereford cattle (a good example to compare to humans, since we're both mammals) got started in 1934, and is still going.  And in that case, they purposely continued to inbreed, rather than outbreed, which would be possible with humans. However, Line 1 is the only one left.  The other ones died off.

Years ago, one article in Scientific American addressed this exact issue.  As I recall, they said that best estimates is that it requires a minimum population of around 200,000 adults of breeding age in order to established the necessary human genetic diversity.

> What is the vary least that it can take?
Two, but they'd have to be two people who had absolutely no deleterious recessive alleles.