Pointless, perhaps. But eminently profitable. The plain fact that internet traffic in pornography is significantly higher than any other kind of traffic points to Kinsey's forgivable lack of prescience. But the man himself as a biopic topic? He's tailor made, rallying against ignorance in the same way Gandhi rallied against colonial rule – for most of their very different but extraordinary lives.

Those sensitive to certain cuss words may want to find a less 'cuss wordy' review but how the hell (sorry, but it gets a lot worse) can you review a movie about Alfred Kinsey without a few 'fucks' scattered around the page? After all, Kinsey has the reputation of placing the act of procreation in its more natural fucking state and pushing ignorance to its rightful state – oh no, definitely not bliss, nor Indiana. To those less easily offended souls who are still with me, my thanks.

People of science risk a great deal taking on human sex. It's the one subject that unites us, divides us, frightens us and excites us and, if we have a religious bent (and what belief system, religiously speaking, is not bent in some way?) it tightly straitjackets us. Sex forces us to reveal something eerily profound (if only to ourselves) about our most primal, urgent and basest nature against our better (?) and wholly invented natures. Morality cannot easily be foist upon the act of procreation (and therefore sex) because sex is procreative. It always bothered me that many men and women serving their gods would deny themselves this apparently god-given pleasure. If you accept man's place in the animal kingdom then you have to surmise we have animal instincts, desires and procreative needs. Are they good or bad? Is the Bonobo pygmy chimp good or bad while screwing every other pygmy chimp in his or her immediate surroundings? He's our closest relative but rarely gets invited to dinner parties. He'd no sooner praise your petite fours than hump his mother. Better leave him off the guest list for now.

Procreation is natural and therefore, one can assume, morality free – if we are simple animals. What about killing people? Probably wrong in a tempered, moral world, a world in which we do not live. Killing in the lap of 'Mother Nature' is unequivocally acceptable (and therefore a staple ingredient in certain natural history films, snuff movies by any other name, but wholly tolerable snuff movies if 'The Natural World' is to be believed). Creating people, the very opposite? Even educated fleas do it. But still the scent of impropriety swirls around sex like wafts of musty guilt in a confession box. For a long time (and thankfully this is changing), the British Board of Film Classification would come down hard on sex while letting violence bleed through. Sex and violence, Mary Whitehouse's pet peeves. I keep wondering what happened in that woman's life that led her to such blanket denunciations. I would not like to have been stuck in a room with her parents.

There are many debates (that come up in Kinsey) concerning those that have sex with procreatively inappropriate partners. I am not lumping these assigned categories together in any judgemental sense. They exist side by side only by the simple fact that the sexual acts in these instances are not procreative. Under scientific scrutiny are homosexuals and a wider net-casting snares paedophiles, omniphiles (ask Bill Condon, the writer/director – I assume it's folks who have sex with everything but it's not in my dictionary) and those that enjoy the mute company of selected animals. But what scuppers any rational scientific analysis on a subject so dear to the advertiser's heart is the fact that sex is the spaghetti to the human bolognese. It is so complexly entwined with human experience that to be rational about it is like being capable of taking the N out of DNA. Yes, one can be rational about the physicality and the actual act and its measurable, quantifiable aspects and effects on the human being. But, and this is what makes Kinsey so compelling, how do you manage to strip away the e-motions from going through the motions?

You don't. That's the rub. And that's what the movie Kinsey does so well. It frivolously and knowingly pretends (very much from the Professor's point of view) that sexuality and love can always be separated and one of them pored over and studied. His own marriage is a hot bed (naturally) of instances where the two forces collide and yet he blithely sets out on his admirable mission realising along the way that it's not the sex part that holds the meaning – if there is any meaning to love. Biology is provable science. Love is elusive and powerful, like Genghis Kahn hiding behind a tree.

There are powerful and contradictory emotions swirling about Kinsey, the awkward stuff that makes you evaluate and re-evaluate what you are seeing every five minutes or so. In the forties after the second world war, Professor Alfred Kinsey, to his eternal credit, attempted to demystify the abject delusions and the ignorance that sex (and the fear of sex) had created. No. Let's lay the cards on the table. Sex didn't create the ignorance. Religion had regulated sex as a procreative act. If you want kids, marry and fuck away. If you want carnal pleasure without the responsibility of bringing up offspring, then shame on you. No, preacher. Shame on you.

We are designed to fuck, not to adhere to belief systems that literally did go out with the Ark. We have interlocking parts. We are made to make other people even if this is not one's immediate aim. We were given bodies that could experience intense pleasure. Where is the key to the man-made lock of our chastity? If you push a button and an intimate partner smiles and goes 'Oh!' then surely button pushing is a positive force for good? Someone once signed a leaving card to me "life is a sexually transmitted disease" and it was only after many years that I fully understood the profundity of the 'joke'. That the procreative act is so mindlessly glorious is, to me, not the cosmic joke of a wayward, odd god. It's a simple scientific fact. We are physically rewarded with the orgasm because biologically doing so we make babies, our genetic aerogram to the future. If we need to set up rigid belief systems, why can't they be based on a pleasure principal?

What's this 'sin' stuff actually for? Is it simply to control the masses? The sin aspect is as misguided as it is akin to a company manufacturing guns where the board of directors is outraged when it learns that the products actually fire bullets. That pandas have a low sex drive (and, granted, a habitat destroyed by our own ambition) almost guarantees their extinction. The human being is far from extinct. Men and women (to concentrate on what's seen as the so called 'normal' union for just a moment) are so extraordinarily different in their needs and desires, that some see this pointing in the direction of proof of an Almighty. Really?

Men (it is believed) routinely cast their seed 'willy nilly' (another phrase for impotence?) because they are driven to experience as many orgasms as their brief lives may allow. Women, who grow life in their own bodies, are (generally speaking) choosier about their partners. A great poet (Lord Byron) said it in more (granted) poetic terms: "Man's love is of man's life a part; it is a woman's whole existence. In her first passion, a woman loves her lover, in all the others all she loves is love." Well, that's not really Kinsey's area but it does point to the single aspect of sexuality that Kinsey really didn't get around to – love.

Love. This is acknowledged in the closing moments of the film and very glad I was for this inclusion.

Love is sex's tag partner (sometimes absent, sometimes more than present) but an invisible one, one that needn't be there for the sex to be fulfilling. Sex is physical, pleasurable, mindful of the shutting out all that is not orgasmic. Love is something else. We all have our own relationship with love and all of its different manifestations. Hell, there's even a love of money. But then if we are all different (something Kinsey championed based on his research on insects), generalities do not apply. I have always thought that the following statement, generally applied to both male and female, has some frighteningly stark truth to it – "If you're hot, you're hot. If you're not, you're not." Men and women, men and men, women and women, men and goats… (maybe not from the goat's point of view), this sharp nick of truth works for me.

Bill Condon's Kinsey is a mature work, a grown up film for grown ups that underlines the ignorance at the heart of any so called civilised western society when sex rears its head. To the director's credit, he has his name appear boldly superimposed over Kinsey as a youth vigorously pleasuring himself. Fuck it. He's masturbating. Euphemisms are for wimps. It's a detail Condon proudly underlines in the commentary. In a deleted scene, Neeson argues that "At least I'm aware of my own ignorance…" It's a telling statement that didn't make it into the finished movie but to be aware of what one doesn't know is a wisdom all of its own. To want to find out, given the society in which you live, is either great folly or takes great courage. Kinsey went for it, published it and was damned and praised in equal measure.

People both wanted and didn't want to know what was going on behind closed doors. The fact that what mostly went on behind closed doors were also ther machinations of closed minds is something that percolates up, giving Kinsey's research (and indeed life) a potency they would not have achieved had the USA been The Netherlands. The nether regions were private parts. You were either brought up to celebrate your physicality or fear it. Science is about the removal of fear. Science is about the removal of superstition and belief systems that enslave and oppress. But then, we are talking about the western world. Look at the furore over Lewinsky's stained dress and flipping over to HBO you could see Samantha going for it, naked and big time on Sex in the City. Has there ever been such a country of absolute polar opposites? I was heartened to hear an American friend of mine comment thus on Clinton's Lewinskygate: "What's all the fuss about a guy getting a blow job?" This was Kinsey's country, the melting pot in which he pitched his life's work.

After a hesitant and misjudged start to his own sexual life, the great man decided to figure out what was so intoxicatingly beyond reach in understanding mankind's fear, love and obsession with sex. He trained research students to ask the right questions, to give out the right body language to put people at their ease. He gathered an extraordinary body of work that was published and suddenly America had a new hero, a new villain, a new religious hate figure who would be perplexed why people reacted so strongly against his seminal (!) works.

At a lecture early in the film, you are treated to shots of an erect penis nestled almost leisurely against the lips of a vagina. It's not a CG effect (cinematically we are not that far gone, not yet anyway) and draws gasps from his audience, his real audience within the movie. It's certainly a shock but then you have to temper this with the strange fact that if statistics are to be believed then what we are seeing in the bold light of day is a photograph of parts of the body that people on average bring together twice or three times a week. Statistically, these images are mundane but just look what we've done to sex to force it into the realms of pornography.

I'm not advocating that we should all start enjoying pornography willy nilly (don't you just love that phrase?). I work in the Netherlands on occasion and a few years ago found myself reaching for a newspaper. Standing up straight, my line of sight fixed upon a medium to top row of glossy magazines, I couldn't quite believe what my eyes settled on. It was 8 o'clock in the morning which didn't make it worse, just somewhat surreal. A beaming young nubile woman smiled out at me, her face covered in… Hang on. I'll leave that to your imagination despite little being left to mine. It was genuinely shocking but my first instinct was not to suppress it or censor it in any way. Another aspect of pornography that has me puzzled is the enormity of the industry when the actual moment of truth for men lasts seconds and for women? That's a mystery and I wouldn't even attempt to put a 'from 'x' to 'y' figure on their orgasmic durations. But Kinsey would.

The movie deals honestly with a very tricky subject (the human being just in case none of you were taking notes). Neeson is a giant of a man and his performance is understated and wholly convincing even if his accent did put me in mind of Hopkins' turn as Hannibal Lecter. Laura Linney (as Condon points out in his somewhat gushing commentary) is the heart of the movie, the woman who has the audiences' sensibilities. If she can be brought around to another way of thinking, maybe an audience can be too. Kinsey's researchers are all famous actors in their own right (notably an older Timothy Hutton, a rampant Chris O'Donnell and giving a touching and unusually sensitive performance, Peter Sarsgaard). According to the director, all the bittiest parts are played by actors of great theatrical renown but stealing the scenes in which he features is a towering John Lithgow. The man has to be a righteous bastard with no humour who makes you glad you live in this century not his – so why is he so entertaining? He has to make Neeson wither (no small feat) but he also has to play an excruciatingly frank scene with his son over the denial of his own sexuality. The fact he plays it with a phallic cigar in his hand and a near tear in his eye is a testament to the man's skill. He's wound tighter than a marquee guy rope and underneath the bluster you feel that he knows it. Underused is one of my favourite actresses (it turns out she was also a victim of late excising), Veronica Cartwright. She only has to deliver a look and it's enough.

But the real kicker, performance wise, I have to mention is Lynn Redgrave's. Her heartfelt one on one with Kinsey at the end of the film packs an enormous emotional wallop and it is given some measure of power in hindsight as Condon informs us that she had just got through cancer. Kinsey gave her character a key to her life and it's really moving. It also pricks at a larger truth, a frustration that sex inhibits people so much. That's what Kinsey wanted to reveal, to unleash and if in part he was successful, we should all be extraordinarily grateful.

The movie is a talk-fest (yes, there is some sex in it) and given that this DVD was not viewed on a fully functioning 5.1 surround system, I cannot comment on its aural tricks but then it's a talking movie and tricks would detract. Carter Burwell's score is noteworthy, managing to pull together disparate editing choices with a full on emotional and lyrical score. Frederick Elms' cinematography is faithfully recreated on the DVD with a very warm and period attentive detail but quite unlike movies that seem to want you to be certain they did all their research. Elms, like all great cinematographers, is into the communication of the emotion and his work is exemplary.

Condon's commentary (as to be expected from the man whose commentary on his own Gods and Monsters was wonderfully revealing) is more studied this time out but never dull and always quietly revelatory. Kinsey is a huge subject and no one hour and forty-five minutes is going to do the man justice so Condon fills in a few blanks. Also notable are the remarks made showing Condon's respect for the greats. He cites Vertigo as 'the greatest movie ever made' (not too many arguments from where I'm sitting) and the fact that Kinsey (technically speaking) was a movie co-directed by Condon and a certain John Ford. One of Ford's forces' V.D. Awareness documentaries pops up in Kinsey, something that Condon gleefully reveals. He also mentions a scene in which Neeson is naked (in the mid shot, he clearly isn't) and that the film makers were worried about the MPAA's reaction to the film's explicit dealing with sex and all its varied offshoots. One of his happiest moments on the production was getting word back from the censors – they gave it an 'R', not the dreaded rating above which would have dumped the movie into unprofitability – the word came back "Thank you. We learned a lot."

The other offerings are:

Deleted Scenes – again, Condon takes us through the brief snippets of scenes snipped for reasons mostly of pace. Chris O'Donnell seemed to have come off the worst, his best work being deleted. Nice to see the Albertus font popping up again.

Gag Reel – not a real side splitter but fun as an inclusion.

Inside Look – a 20th Century Fox advert essentially including the trailer for Kingdom of Heaven a few other Fox productions and a featurette on the charming Sideways.

For anyone interested in how sex wrenched itself from the straitjacket of religious control, Kinsey's your movie. Neeson is terrific, Linney centres the emotional undercurrent, Lithgow is scary but compelling and Lynn Redgrave knocks your socks off. The whole film is a powerful nod to and against the forces that keep our true natures in check.