Here is a look at some of the siblings who will be competing in biathlon at the 2014 Sochi Winter Olympics.
Valj Semerenko of Ukraine is a six-time European champion and won silver in the relay and bronze in the 15km individual at the 2013 World Championships. One of her teammates on that relay was her sister Vita, who is a five-time European champion and won sprint bronze at the 2013 Worlds.
Twins Tracy and Lanny Barnes competed together for the U.S. biathlon team at the Sochi Olympics in 2006. Tracy qualified for the 2014 Sochi Games but relinquished her spot on the team to Lanny, who had fallen ill during the Trials and would not have made the squad.