I was first attracted to it bcos the early B&W episdes resemble early HK martial arts movies in a way and the Doctor was often played by elderly or late middle age actors but the more recent doctors were younger. The doctor is an extraterrestrial alien in human form and he often got attractive human female companions/assistants.. But seems the good doctor is not capable of human sex. Some said the doctor is a fag(even one of the actors said so) but I disagree. And there's I would say a good deal of sexual tension.

http://www.thegeektwins.com/2014/08/7-hottest-female-companions-of-doctor.html#.Vg2BlduhdrQ

http://www.independent.co.uk/arts-entertainment/tv/news/doctor-who-used-to-promote-homosexuality-according-to-complaints-to-bbc-9947094.html