Worf's son is known as Alexander Rozhenko. There are some aspects about that name that I can't fully understand, and I'm hoping for an in-universe explanation. Where did this name come from?
His mother, K'Ehleyr, didn't tell Worf about her new-born son (as implied by TNG 4x07 "Reunion"), so I guess Alexander wasn't officially registered as Worf's son. In that period, before K'Ehleyr informed Worf, he can't have had the last name of Rozhenko - that wouldn't make sense.
After the events that happened in "Reunion", Alexander was now officially acknowledged as Worf's son, which might have led to a change of his name.
But would Worf have chosen to follow a Human naming pattern for his son instead of a Klingon pattern like "Alexander, son of Worf"? My feeling is that Worf would have preferred the Klingon way for his son.
I don't think the Rozhenko couple adopted Alexander, thus giving him their last name. He's always referred to as Worf's son, and Worf's adoptive parents just took care of him for some time.
Did I miss something? I'm not only interested in citations of official sources, but also plausible interpretations.