The Cox YDNA Project has nearly 1,000 members. The project employs YDNA test results to prove, disprove, or identify unique lines of Cox families around the world. Only men possess the Y Chromosome which is passed from father to son, to son and so on. This chromosome can match two men who share a common paternal-line ancestor over 1,000 years ago. Women can participate by recruiting a Cox brother, uncle, nephew or other male relative to surrogate test for them. Individuals can also join the project (male or female) using their autosomal test results from ancestry.com, 23andMe or other system. These results can be transferred to FTDNA.com for free.