Answer
Yes, Niels Ryberg Finsen had eight siblings. His father, Wilhelm Nicolai Finsen, was a wine merchant and his mother, Ingeborg Elisabeth, was the daughter of a vicar. Niels Ryberg was the 10th of 11 children, with 2 siblings dying in infancy. The Finsen family was very close and supportive, and Niels Ryberg's siblings were all very successful in their own right.