Not that many actually, the estimations about people being made of more non self stuff than selfstuff were based on no serious measurement and its more of an urban legend than a fact.
Current estimates are that there are slightly more bacteria than human cells (3.8x10^13 vs 3.0x10^13) in a "reference man". However, the mass of the bacteria is only 0.2kg, so human cells totally dominate by mass. Interestingly, most of the human cells by count are red blood cells.
Nope. Its no urban legend. Recent findings now suggest there are free tissue bacteria species previously unknown about in humans. So the numbers of bacterial cells to human is only going up with understanding not down.
