Sergey and Helena Rozhenko are foster parent to Worf.
Sergey Rozhenko was a Human male who served as a Starfleet chief petty officer and warp field specialist during the 24th century. He was married to Helena Rozhenko and together they had a son, Nikolai Rozhenko. In 2346, Sergey Rozhenko served aboard the USS Intrepid, when the ship answered a Klingon distress call following the Romulan attack on the Khitomer outpost. In the wreckage of the outpost, Sergey discovered a young Klingon named Worf. Through an act of kindness, Sergey and Helena fostered Worf.