'Back to the Future day' has passed with lots of discussion not just about how well the film predicted 2015, but also about the changes we can look forward to in another 25 years' time. While much was made of the technological changes, the biggest surprises for Marty, fast forwarding from the 1980's, would surely have been the social ones. Without doubt, the biggest single cultural change has been the new (first) world order regarding sexuality. In just two decades homosexuality has moved from the margins of society to having mainstream cultural recognition and indeed celebration. The move to legal civil partnerships and then to same-sex marriage has been remarkable – for it to have happened in such a small space of time is really quite astonishing.

It is a reminder that, culturally, anything really is possible and that the societal norms of 2040 may be staggeringly removed from those we assume at the present time. So are there any clues as to where we might be heading next? I suspect that one good indicator of forthcoming cultural change would be to see what movie and television projects are currently being pitched to media companies. After all, the current slew of programmes and films generating debate and shaping popular thinking must have started life, in some cases, several years ago.

Transgender: the new frontier

It is clear that with homosexuality firmly established in the mainstream, the new frontier for culture re-shapers is now gender itself. Recent months have seen a succession of stories and programmes in the media concerning transgender. BBC 5-Live has interviewed an 11 year old girl starting high school as a boy, Louis Theroux has been looking at transgender kids, Channel 4 have a series of documentaries running on the subject, a new transgender sitcom 'Boy meets Girl' has been commissioned by BBC2, transgender is now an 'East Enders' storyline, and Hollywood A-lister Eddie Redmayne has starred in this year's release 'The Danish Girl' the story of an early pioneer of transgender surgery.

The approach to the issue is the same in all these presentations – to be supportive, to show the bravery of those involved (and many of them undoubtedly are courageous), to render churlish and ignorant any opposition to or questioning of those involved, to win the sympathy of the viewer and to make it mainstream. It is no surprise then that 'transphobia' is becoming the latest addition to popular vocabulary.

The Daily Telegraph reported a four-fold increase in the number of under-10s being referred for transgender issues. Anecdotally more and more schools, workplaces, clubs and churches are having to adjust to and work out how to interact with transgender situations.

Transgender feelings, of course, aren't a new phenomenon, but the advent of modern surgery and hormone treatments have made it possible to turn such desires into a reality (of sorts). But lying behind the medical issue is a much deeper philosophical issue concerning the nature of humanness itself. It is the notion that sexuality, and in this case physicality, are 'plastic' aspects of personhood. That is, 'I' am not to be defined by my gender when it comes either to relationships or who 'I' actually am. So my physicality is arbitrary – just a random imposition of biology which may or may not suit me and, like a set of clothes that I may find hideous, ought to be changeable.

So on current trends it is entirely feasible that by 2040 many children will routinely dress and attend school in a gender different from their biology. Gender based language and pronouns may be phased out in public life. Names may increasingly be unisex, as giving a child a 'gender specific' name will be frowned upon or seen as constraining them. Switching gender identity between certain situations or phases of life might become commonplace.

Responding to a Cultural Tsunami

For Bible-believing Christians this is another wave of the tsunami of cultural change experienced over recent decades. But how should we respond? That is a question, of course, that might understandably fill us with a sense of dread and/or weariness. After all we look back at the campaigns against Civil Partnerships and Same Sex Marriage and see how the opposition to them was swept aside. Like the boy crying 'wolf' we feel our protestations have worn thin in the ears of those around us – especially as, for the time being at least, society has not collapsed into chaos despite having ignored us.

Well there are various ways we could go. One would be to demand legislation to prohibit people from making transgender changes, at the very least to lobby against any moves to accommodate transgender people in mainstream society. The problem with this approach is two-fold. Firstly it is trying to impose a Christian worldview on a non-Christian society and thus trying to sanctify the unjustified. Secondly, and precisely because of the first reason, it just won't 'wash' with a fragmented neo-pagan society of competing interests.

We could of course do nothing, say nothing and just resign ourselves to further inexorable moral confusion. That, however, would be an abdication of our responsibility to be "salt and light" in the world, to seek the lost, and to hold out the word of life in a crooked and twisted generation (Php 2:15). So how do we stand for biblical truth without presenting ourselves as being oppressive towards transgender people or anyone else?

Let me suggest we firstly have to recognise that there are those around us who genuinely struggle with their gender. For those people their gender is an issue of confusion and sometimes real pain and unhappiness. We have to accept that science and the government have given such people the option to radically alter their physicality and the option to live in a changed gender. That people have those options should not be our first point of concern.

There is an alternative

Rather than 'slam and ban' we need to lovingly make the case that there is another way someone can go in such situations. As Christians we want to say that there is an alternative to fear and embarrassment in relationships, to injections in the stomach, radical surgery, family confusion, ongoing physical and mental health problems and many of the other possible consequences of pursuing gender change.

That alternative, of course, is the gospel. The gospel that reveals the God who made each person – who made them male and who made them female. The God who didn't make a mistake when He did that. The gospel that explains that we live in a fallen world and because of that there is no aspect of our humanness that isn't messed up to a greater or lesser degree. The gospel that shows that God is nonetheless committed to recovering this world and restoring men and women to being what He intended them to be – good and glorious, happy in their own skins and able to enjoy Him for ever. The gospel that doesn't oppress anyone, but offers men and women a way to find their fullest and most satisfying identity in Jesus Christ whether in 1989, 2015 or 2040.

Andy Hunter is the FIEC Scotland Director.