We have published a method whereby the year of birth may be calculated to within +/-1.5 years by analysing the 14 C content of the eye lens, following a seminal study by Spalding et al. [82] using dental enamel. The method is based on the fact that all living tissues undergo a continuous turnover, substitution and remodelling [e.g. 83], both on Figure 11. Agreement between odontological and GPA age estimation. Horizontal lines indicate the age span given by the odontologist; X = age estimate by two of the authors; O = age estimate by radiologists. Figure 12. Age at death in relation to the degree of aspartic acid racemization in collagen from first permanent molar teeth from 32 subjects. D/L-Asp , ratio between D-aspartic acid and L-aspartic acid. The arrow indicates a second permanent molar from a 27 years old subject; the **data** point is plotted at 27-6 = 21 years to simulate the true age of the tooth, and shows that this corrected **data** point did not deviate from the results obtained using the first molars.  Table 4. Determination of the age of 6 subjects from measurements of the degree of aspartic acid racemization in collagen from first permanent molar teeth. D/L-Asp, ratio between the D-and L-enantiomers of aspartic acid. Age is in years.