Whilst it should come as no surprise to anyone that there are lots of stupid members of the US Congress, the case in this report on The Daily Mail really takes the biscuit!

Representative Jason Crow is quoted as saying "You can take someone's DNA and design a weapon that can kill them" and that bio-weapons are being made that use a target's DNA to only kill that person. He urges people not to share their DNA with health data with sites like 23andMe.

There are a couple of problems with his statements:

1. Although someone's raw DNA can technically be used to design a weapon to target them, the DNA results that health and genealogy sites produce cannot. The tests work by chemically chopping the DNA at sites with specific DNA bases, and then using chromatography to show the number of fragments with various different lengths. These tests do not produce a complete map of a person's genome, which is what is needed to develop a weapon of the type that Jason Crow describes. These companies do, of course, need original raw DNA to conduct their tests, and the tests are often outsourced to labs in other countries like Russia and China, meaning that these other countries will get your DNA, and could create a targeted weapon.
2. Complete genome mapping is an expensive and time-consuming process. The development of a targeted weapon from that genome map is an even more expensive and time-consuming process. This is why gene therapy medicine is still rare, although possible, and exorbitantly expensive. If you want to kill someone, it would be quicker and simpler to just hire a hit-man (even a top-quality, very expensive hit-man). Of course, improved technology is constantly driving down the time and cost of such genetic work, but there is a very long way to go before such targeted bio-weapons become viable.

I do, however, agree that it is not a good idea to share your DNA with such companies, nor indeed with anyone, for various reasons including the fact that some of these companies share your DNA with law enforcement agencies. Plus, of course, at some point the targeted bio-weapons that Jason Crow is worried about will become viable as prices continue to fall.