The director of the first ever series of Doctor Who has said there has been a "sea change" in the BBC's hit show with a new element of "sexuality".
Waris Hussein worked on the science fiction programme in 1963, when William Hartnell starred as the Time Lord.
"There is an element now, and I know we're living in a different era, of sexuality that has crept in," he said in an interview for BBC Radio 4.
"Why bring in this element when in fact you needn't have it there?," he added.
Part two of the seventh series, starring Matt Smith, began on 30 March.
Described by the current writer Steven Moffat as an "urban thriller", the first episode of 2013 was set in the present day.
Smith, who has played the Doctor since 2010, was joined by a new companion - Clara Oswald, played by Jenna-Louise Coleman.
But Hussein, who appeared on Radio 4's The Reunion with previous cast members, including Peter Purves and Carole Ann Ford, said there was no need for a romantic relationship between the two.
"The intriguing thing about the original person, was that you never quite knew about him and there was a mystery and an unavailability about him," said Hussein.
"Now we've just had a recent rebirth and another girl has joined us, a companion, she actually snogged him."
He added that the Doctor should be more like the character of Sherlock Holmes, saying: "Why bring in this element when in fact you needn't have it there?"
Purves, who became a Blue Peter presenter after a stint as the Doctor's companion Steven Taylor, said he agreed "totally" with Hussein and said storylines had become too complicated.
"The original series was so simple. They were very straightforward, nice linear stories that one could follow," he said.
Doctor Who is celebrating its 50th anniversary this year with a special 3D episode which will see Smith joined by former stars of the hit show including Billie Piper and David Tennant - who played the tenth Doctor from 2005 to 2010.
The current series opener on 30 March attracted 6.2 million viewers, but fell to 5.5 million for the second episode, The Rings of Akhaten, broadcast on Saturday 6 April.
However, the audience was slightly bigger than the second episode of the sixth series, Day of the Moon, which brought in 5.4 million viewers, according to official figures.
There was a mixed response from fans who watched Saturday night's episode with some taking to Twitter to express their opinion.
Others who enjoyed the show included @TheVodkaYeti who said: "Really liked The Rings of Akhaten, adorable episode, some fresh ideas, good performances & Clara's character coming along nicely," while Suzanne @dancing_arya tweeted: "That was easily the best best BEST episode that Matt Smith has even done as the Doctor. Bravo, just bravo!"
In a statement a BBC spokeswoman said: "The series is in fine form and Jenna-Louise is a big hit with viewers."