[rouli]

This is fun! I took the boys average weight data given in [1]

months from conception, average weight (kilos)

(9, 3.25)

(15, 7.5)

(21, 9.97)

(33, 12.88)

(45, 14.97)

(69, 18.97)

and saw that it really looks like a logarithmic function. So, fitted y to log(x), got y~7.4685*log(x)-13, with R^2=0.9965 (thank you R!). Extrapolated back, and found that at conception, the fetus weighs -inf kilos. Not surprising result, I must say. However, I was surprised to find that only after five months of gestation, the embryo reaches the critical mass of 0 kilos. Science!

[1] http://www.buzzle.com/articles/average-weight-for-children-b...