I typed the whole thing up and now see that people have already typed up some main bits. But my fingers are aching, so sod it, I'm posting it anyway 
Presenter: What is a woman then, how do we actually define a woman, a lot of politicians are struggling with this now.
Lord Winston: I don't think defining anybody is quite the right question to ask, I think what we need to ask is 'what is the fundamental difference between men and women, or between boys and girls, between the two sexes', and there are fundamental differences which are quite clear.
With regard to being a w- I think there's a bit of confusion here between sex, ones sex and ones gender, and of course gender reassignment is possible to have organs removed and other mutilations, including for example giving drugs which might change the way you feel and how your body behaves, but that's not the same as changing your sex. You can't change your sex, because your sex is defined in quite a different way.
There are 5 ways we can define sex, one of course is basically how we look, for example having sex organs, breasts, a penis, a uterus and so on. That's one way and that can be changed of course because you can actually remove breasts, remove a uterus, you can actually change the morphology, the shape of the human body by doing that, but of course it is a form of mutilation, doing that.
Presenter: On that point then about being able to recognise those differences by using your eyes, something I think we've done throughout the ages...on the issue about what's widely covered in the press about the participation of transwomen, or biological men, in women's sports, what are the physical elements that are...going through puberty as a biological male actually mean that you have a biological advantage over women in certain sports?
LW: Well that comes to...that's another definition of sex, basically. The key definition of sex is your genetic sex. Basically every single cell in your body is created by genes and is controlled by genes, so for example you have about 7 or 8 trillion cells in your body, and if you're a woman you have two X chromosomes with the female carrying characteristics, and if you are a male, or a boy, you have a Y chromosome which carries around 40 genes all of which indicate (?might have misheard 'indicate', sound went funny) your sex.
Now, you cannot change that by simply operating on somebody or giving them hormones, because you still have the Y chromosome. And so one of the risks in regards to sport is that somebody who has male characteristics will have been at some stage, from the time they were in the uterus onwards, associated with hormones which are gradually developing their musculature and other things which would clearly give them an advantage over a woman.
Now, even if you change the body after puberty, or in some cases even before puberty, the fact is it is probable you will have different characteristics as a result of that. Now, this issue is of course, nobody has ever done any proper research just to see how this is, and one of the difficulties is, because the whole issue of 'transgender' is so complex, and so much criticism as soon as you come on the media and mention that you believe the things that I am saying are biologically true, are scientifically certain. You come under immense criticism, so doctors and physiologists and myself tend to not put their head above the parapet. But actually, that's one of the reasons...
Presenter interrupting: And that is truly damaging for debate and speech, I mean you standing up in the House of Lords in the upper chamber, and saying that as part of the maternity bill when the attorney general would have had to resign in order to actually go on maternity leave, and part of this bill said 'pregnant people', if I've got that right, instead of women. See, I cannot get pregnant, for example, as you well know, so I want to just ask about that bill in particular, why do you think there has been this increase in this changing of language and words that have been accepted for many, many years in this country?
LW: I think there is pressure from the transgender community which is understandable. I have nothing against transgender people, they are perfectly welcome as far as I'm concerned to behave, or dress like a female or a male, that's entirely up to them. But there are certain things that they can't change, and one of the things you can't change is to actually have a baby- it's not possible for a male to have a baby. In fact, nobody has ever managed to do this although there have been many people who have changed their sex from female to male, who've subsequently as a fertility surgeon asked me if I would try and help them have a baby, I've had requests from males to have babies.
(I think above he may have been muddled and meant MtF have asked him to help them have a baby, not FtM judging by the next bit...)
LW: The only way you could do that would be by implanting an embryo directly into the abdomen, where of course it would grow rather like a tumour, and would risk the life of the individual, which is of course why nobody has done that...
Even transplanting a uterus, which is technically just possible, you might eventually be able to have somebody who is pregnant and male, but the risks would be so great that no surgeon, no doctor would contemplate it.
The other problem of course is this, that if 'transgender' is a normal procedure, then the question is should the NHS be expected to pay for this. Because if people in fact have a problem with their sex, to what extent is this an illness or is it just a condition they want to change? And the NHS, under pressure as it is, may decide of course that these are things it shouldn't be accomplishing. At the moment the NHS is also in a tangle with how they should handle people who are transgender, what sort of ward they should be in, and whether or not they should have the sort of hormones...
Now at the moment, an indication has gone out to GPs that they are allowed to give the hormones to change someone's hormonal state, at puberty. My own view is, I think this is quite dangerous, but it is something which is accepted in some quarters...
Presenter: Robert, I wonder if you've had any reflections, just briefly there because we're coming to the end, why do you think there have been massive increases... I left school in 2009, if you look at the %, the number of children who say they are experiencing gender dysphoria, there can't just have been a massive increase of people experiencing it, can there?
LW: We've always had that, I don't doubt that you, certainly I, and most normal males and normal females at some time have questioned their genitals and worried that they're not quite right. It's very, very common, and before puberty of course there is considerable confusion about ones sex, at a time when ones hormones are developing and one is changing into an adult. It is a massive time of considerable concern for everybody, it's quite usual.
Of course, the risk is that you can confuse that concern in to some status which it perhaps isn't. What I would want to say finally is I've seen so many people in my practice as a fertility specialist who desperately wanted a baby after a sex change, and found to their horror that it wasn't possible, and that's caused them immense distress and depression, and some have even tried to commit suicide. So I think it's a very, very serious issue.
Presenter: Yes, and I think we aren't talking about the risks and harms potentially imposed by medical intervention enough. Do you agree with that?
LW: Well I think that's one of the risks, but I think of course that what we've got to now is a situation of political correctness about the nature of gender, and I think that's not particularly satisfactory, because political correctness does not in fact get to the real truth of the issue.