I found Falconeer's review most convincing. Therefore the following cites Falconeer (by "") at some points, while adding several own thoughts.
First -- I can only underline Falconeer's remark that "the creators obviously have an almost reverent love and respect for this special time of life before we must accept responsibility ... So I find it profoundly sad to read so many people trashing this movie, based on the scenes where the kids are playing and swimming plainly nude." Having surmounted the threshold of doing away with their clothes, "the characters don't even seem to be aware" any more of any peculiarities "of their being naked, so I have to wonder why it is such a big deal for the adult audience ... kids ... would have a deeper understanding of it than many adults". Yes, indeed.
Second -- "Genesis Children is showing the difficult journey that we all take" in order to become what we always were, and to that end the boys are taking part in a 'play to be performed before God'. At a certain point close to the end of the film, after having engaged in a 'ritual' of burning an old van which they had rammed into their self-built shelter the day before, a turning point of the play is reached, where some of the boys decide to leave the place and the play. Here I locate what is perhaps the central sentence of the film: 'Aren't you going home?' asks one of those who have put on clothes again and are about to leave. 'I am home', replies one of those who stay. In a somewhat cryptic manner one could say that some have not moved during the play and are therefore bound to leave and continue their quest for 'home', while the others do have moved and therefore can stay.
Now I want to put forward another essential point. One can view the message of this film as the third part of a trilogy. On Aikman's own home page (still available) there is noted 'Often compared to Lord of the Flies'. This other classic, filmed after the famous novel by William Golding just 10 years before The Genesis Children, refers in turn quite explicitly to Ballantine's novel 'Coral Island' from the mid-19th century. In all 3 cases the theme is the acting of a group of (male) kids left alone on some island or shore (i.e. deprived of a direct civilized environment and set out in a purely natural setting), with an undertone of investigating where evil comes from or how it is overcome. But while in Ballantine's novel the point of view is clearly optimistic in the colonial sense common in the 19th century (Wikipedia: 'obsessed with the purity of God, Trade and the Nation, and written for the future rulers of the world'), Golding decidedly destroys the optimistic world-view of a self-proclaimed master-race. In his story, which like Ballantine's still features dominance, struggle and victory or defeat, these impulses do not create an ever growing sphere of ordered civilisation, but lead into complete destruction within the shortest possible time. Here Aikman's film appears as a response to Golding's 'solution', and its purpose is, I believe, to feature less crude impulses than dominance or struggle and victory. There is never aggression or any struggling for dominance between these children, who in the beginning practise a fully cooperative way of living with astonishing ease and great naturalness. I think Aikman wants to show that this way of living is endangered in the first place in a more subtle way -- 'boredom, hunger and homesickness were our enemies, and that's why we started to argue'. Instead of aggression it's a feeling of futility with regard to the quest for 'home' by some of the boys, which finally divides the group.
This leads to my final point. Other reviewers were concerned that so much nudity might be considered a bit gratuitous. Much nudity? If I count all the nudity scenes, I end up with about 1/8 of the film, and even in this moderate part nudity often can only be intuited, because the boys are visible only in the distance as silhouettes against the light or otherwise blurred. The nudity scenes are not to bluntly showcase naked bodies but do have some particular message. They never lack respect and reverence, and above all they are presented as sort of sacred dance and breathe a sabbatical ease and peace, underlined by the music score changing to liturgical songs and church bells and evoking allusions to Psalm 126 ("release of captives"). I wished -- pedophiles-hunters, calm down, there's nothing here for you to get -- they would take 1/4 of the film or more. By the way, that they appear predominantly in the first quarter of the film is also a reference to Lord of the Flies. And gratuitous? I suggest to view it just the other way round: in the natural environment into which the Genesis Children are placed there's no need for a specific reason for being naturally naked, rather there have to be reasons for wearing clothes. And in fact, there are a few scenes where I find it a bit gratuitous that the boys appear more or less clothed. Where Golding sees civilisation compromised and endangered by the brute struggle for dominance exploding to plain war in the end, it seems that Aikman wants to show (among others) civilisation and humanity compromised long before by the much subtler struggle for dominance and by the hiding game clothing is a part of, and he wants to explore what still can compromise when these dangers are removed, and to what extent they can be removed at all. In this sense, there is quite a surprising finale, which rounds out the numerous (but in their essence not explicit) religious overtones of the film.
Btw, it is also a quiet film. Out of 84 min. total runtime just under 25 min. (29%) contain speaking (thereof 6 min. background narrator voice). The rest is underlined by the music score or by just the natural sounds of the beach. I consider this noteworthy.
First -- I can only underline Falconeer's remark that "the creators obviously have an almost reverent love and respect for this special time of life before we must accept responsibility ... So I find it profoundly sad to read so many people trashing this movie, based on the scenes where the kids are playing and swimming plainly nude." Having surmounted the threshold of doing away with their clothes, "the characters don't even seem to be aware" any more of any peculiarities "of their being naked, so I have to wonder why it is such a big deal for the adult audience ... kids ... would have a deeper understanding of it than many adults". Yes, indeed.
Second -- "Genesis Children is showing the difficult journey that we all take" in order to become what we always were, and to that end the boys are taking part in a 'play to be performed before God'. At a certain point close to the end of the film, after having engaged in a 'ritual' of burning an old van which they had rammed into their self-built shelter the day before, a turning point of the play is reached, where some of the boys decide to leave the place and the play. Here I locate what is perhaps the central sentence of the film: 'Aren't you going home?' asks one of those who have put on clothes again and are about to leave. 'I am home', replies one of those who stay. In a somewhat cryptic manner one could say that some have not moved during the play and are therefore bound to leave and continue their quest for 'home', while the others do have moved and therefore can stay.
Now I want to put forward another essential point. One can view the message of this film as the third part of a trilogy. On Aikman's own home page (still available) there is noted 'Often compared to Lord of the Flies'. This other classic, filmed after the famous novel by William Golding just 10 years before The Genesis Children, refers in turn quite explicitly to Ballantine's novel 'Coral Island' from the mid-19th century. In all 3 cases the theme is the acting of a group of (male) kids left alone on some island or shore (i.e. deprived of a direct civilized environment and set out in a purely natural setting), with an undertone of investigating where evil comes from or how it is overcome. But while in Ballantine's novel the point of view is clearly optimistic in the colonial sense common in the 19th century (Wikipedia: 'obsessed with the purity of God, Trade and the Nation, and written for the future rulers of the world'), Golding decidedly destroys the optimistic world-view of a self-proclaimed master-race. In his story, which like Ballantine's still features dominance, struggle and victory or defeat, these impulses do not create an ever growing sphere of ordered civilisation, but lead into complete destruction within the shortest possible time. Here Aikman's film appears as a response to Golding's 'solution', and its purpose is, I believe, to feature less crude impulses than dominance or struggle and victory. There is never aggression or any struggling for dominance between these children, who in the beginning practise a fully cooperative way of living with astonishing ease and great naturalness. I think Aikman wants to show that this way of living is endangered in the first place in a more subtle way -- 'boredom, hunger and homesickness were our enemies, and that's why we started to argue'. Instead of aggression it's a feeling of futility with regard to the quest for 'home' by some of the boys, which finally divides the group.
This leads to my final point. Other reviewers were concerned that so much nudity might be considered a bit gratuitous. Much nudity? If I count all the nudity scenes, I end up with about 1/8 of the film, and even in this moderate part nudity often can only be intuited, because the boys are visible only in the distance as silhouettes against the light or otherwise blurred. The nudity scenes are not to bluntly showcase naked bodies but do have some particular message. They never lack respect and reverence, and above all they are presented as sort of sacred dance and breathe a sabbatical ease and peace, underlined by the music score changing to liturgical songs and church bells and evoking allusions to Psalm 126 ("release of captives"). I wished -- pedophiles-hunters, calm down, there's nothing here for you to get -- they would take 1/4 of the film or more. By the way, that they appear predominantly in the first quarter of the film is also a reference to Lord of the Flies. And gratuitous? I suggest to view it just the other way round: in the natural environment into which the Genesis Children are placed there's no need for a specific reason for being naturally naked, rather there have to be reasons for wearing clothes. And in fact, there are a few scenes where I find it a bit gratuitous that the boys appear more or less clothed. Where Golding sees civilisation compromised and endangered by the brute struggle for dominance exploding to plain war in the end, it seems that Aikman wants to show (among others) civilisation and humanity compromised long before by the much subtler struggle for dominance and by the hiding game clothing is a part of, and he wants to explore what still can compromise when these dangers are removed, and to what extent they can be removed at all. In this sense, there is quite a surprising finale, which rounds out the numerous (but in their essence not explicit) religious overtones of the film.
Btw, it is also a quiet film. Out of 84 min. total runtime just under 25 min. (29%) contain speaking (thereof 6 min. background narrator voice). The rest is underlined by the music score or by just the natural sounds of the beach. I consider this noteworthy.