Isotope analysis
A recent development in forensic science is the isotopic analysis of hair strands. Hair has a recognisable growth rate of 9-11mm per month or 15 cm per year. Human hair growth is primarily a function of diet, especially drinking water intake. The stable isotopic ratios of drinking water are a function of location, and the geology that the water percolates through. Sr, Sr and oxygen isotope variations are different all over the world. These differences in isotopic ratio are then biologically 'set' in our hair as it grows and it has therefore become possible to identify recent geographic histories by the analysis of hair strands. For example, it could be possible to identify whether a terrorist suspect had recently been to a particular location from hair analysis. This hair analysis is a non-invasive method which is becoming very popular in cases that DNA or other traditional means are bringing no answers.
Body hair
Facial hair, as the name suggests, grows primarily on or around one's face. Both men and women experience facial hair growth. Like pubic hair, non-vellus facial hair will begin to grow in around puberty. Moustaches in young men usually begin to grow in at around the age of puberty, although some men may not grow a moustache until they reach late teens or at all. For some cases facial hair development may take longer to mature than in the late teens but a lot of men experience no facial development even at an older age. Facial hair development has often been associated with stress levels.