Will the bosses' sex make a difference to the news we see? Since women war correspondents have become more common, for example, there has been much discussion about whether women report violent conflict differently - whether men concentrate on strategy, and women focus on suffering. There has also been much newsroom debate about whether women are more concerned than their male colleagues about social issues such as child care.
Thirty-nine-year-old Sara Nathan does not think female editors have a special agenda. "Just because Nikki Clarke and I are both women doesn't mean we care about the same things. She's fanatically interested in sport, for example, and I'm not. I'm not convinced of this female-agenda business. I think there's more of a divide between parents and non-parents. I have two children; Nikki has none. To me, that's a great difference."
Nathan is wearing a loose striped top and casual beige skirt. She never wears make-up - lack of time, she says. And her husband does not like it. Then she says she is reading Deborah Tannen's theories about "the unmarked state" - how a man can wear a suit and no one notices, whereas every choice a woman makes about her appearance is a statement. "No, it hasn't changed what I do, but I thought it was an interesting way of looking at things." She is fidgety about being photographed, tucking her legs underneath her on the couch, curling up against the onslaught of publicity the new job has brought her.
The attention has not been welcome.Interviewed by the Times, she made a general comment about women with partners in the arts needing to work full-time. That arrived in print as her calling her husband, composer Malcolm Singer, "feckless". The woman who is going to be responsible for Channel 4's news output is still reeling from her first experience of being news.
Then there is the viperish back-room gossip whispering "tokenism" about Nathan's appointment. She has had to face scrutiny of her working conditions - how, people asked, could she do her job with two young children? At one point, rumour had it that Nathan had negotiated a four-day week; she says she simply told Channel 4 she was not prepared to stay late every day.
The hours at Channel 4 will in any case be an improvement on her last job. After a classic BBC career - traineeship followed by producing and editing jobs on Newsnight, The Money Programme and Breakfast News - 18 months ago she went to Radio 5 to launch what became the award-winning The Magazine. That meant a 5.30am start every day.
She has a tough job ahead of her at Channel 4 News. Viewing figures have dropped below Newsnight's, hovering round the million mark, and have become a standing joke in Private Eye.
There is a feeling in the business that Channel 4 News has become a bit dull.Nathan refuses to reveal the changes she will make until she has told her new staff, but she does confess that she would like to broaden the audience and make the programme less Westminster-oriented. "I know there was a feeling at Channel 4 that it would be quite refreshing for the programme to bring someone in who hadn't spent all their time at ITN," she says.
"The audiences for Channel 4 News tend to be older, maler and more middle- class; I'd like to redress the balance. Also, most people tend to watch only part of each broadcast, rather than the whole 50 minutes, and people tend not to watch it every night, but perhaps twice a week. Not many watch it more than twice a week. Obviously, those are areas I'd like to change."
Like Nathan, 36-year-old Nikki Clarke has also spent all her working life at the BBC. But where Nathan was attached to several programmes, in various roles, Clarke has always worked in the newsroom. She became a TV news editor in 1981, an assistant home news editor in 1983, deputy home news editor in 1988, and deputy foreign news editor in 1989. She was appointed home news editor in 1990.
Under the eyes of a BBC press officer, who insists on sitting in on the interview and taking notes, Clarke is less relaxed than Nathan. But she is just as ready to dismiss the idea of a female news agenda.
"I don't think it's to do with females versus males," she says. "Rather it's a generational difference - men, as well as women, have changed in society."
But there is a problem for newsgatherers that want a female input: it is hard to keep women reporters once they hit their thirties. Women either leave to have children, or try to stay but find that they are not accommodated in their new roles as mothers. Clarke admits this, but insists: "It would be terribly wrong to suggest that you have to make special efforts to help women and that it's not an issue for men. It's wrong to feel that male staff don't have the same worries about child care."
Female reporters who have worked for Clarke say that at times she can be dismissive of their concerns - that her attitude is: "If you're not interested in the tough stuff, you're not on my team." She herself says: "None of the reporters who work for me would ever want to miss the big story."
Or the smaller stories, either. "I'd like to develop coverage outside the M25," she says. "It's my obsession, because of where I come from [Leicester]."
The Six O'Clock News, with over six million viewers, is considered to be the family news-programme, whereas the nine o'clock falls after the watershed. All the candidates for Clarke's job were female. Clarke says she does not feel a particular responsibility to help other women up the ladder, adding that it would be quite wrong to encourage women over men.
She has not, she says, experienced much sexism, although when she first started, "there was a slight view that these were rather strange things that had come into the newsroom". On her first Saturday she had to demonstrate that she knew the difference between a round ball and an oval ball. Since then, however, she has been trusted with sport.
What both Clarke and Nathan agree on is that they have reached the jobs they really wanted. They are not looking to the job after this one, thank you very much. Clarke is firm: "This is it. This is great - moving the battalions about."