I was deeply concerned to read the proposal by Dr Kevin Smith last week, that young men should consider freezing their sperm, around the age of 18 with the promise of artificial fertility even in old age.
The proposal, by bioethicist from Abertay University in Dundee, risks creating a generation that relies on artificial reproduction, instead of the natural method that has sustained humanity throughout our evolution.
Dr Smith's reasoning is that, as men age, their sperm contains an increasing number of genetic mutations. Some of those DNA changes, a small number, are related to health disorders, including schizophrenia and autism.
So far, he and I are in agreement. I have been campaigning for better education, to help young people understand the risks of deferring parenthood too late.
Earlier last month I urged the Education Secretary Nicky Morgan to teach teenagers why they cannot ignore their own most naturally fertile years and rely on technology to deliver their children to order.
But I am wholly opposed to a blanket policy that all young men should freeze their sperm. That is an extreme reaction to a simple problem that can be effectively addressed by better information.
There are good reasons why it might be necessary for a man to freeze his sperm: for instance, he might be about to undergo chemotherapy for cancer, which will damage his fertility or he may face occupational hazards to sperm where freezing might be appropriate.
But there are more reasons why it is a very bad idea for all men to do it.
Fertility and general health are intertwined. You can't have one without the other. The factors that are causing early health problems in Western society are the very ones that are causing infertility: smoking, drinking and obesity.
These are very well known to cause all sorts of serious diseases, from cancer to diabetes and cirrhosis.
But if young men have already frozen their sperm, during their teens, they will have less incentive to stay healthy. The idea that they are damaging their future children, by boozing and gorging, will carry less weight: they will know that they can simply dip into the sperm bank.
Many dads will agree that the years when they were trying to have children were the healthiest of their lives. As well as staying away from risk factors, they were probably eating better and taking more exercise.
This has a benefit for society in general and the health service in particular. Anything that spurs young men to take better care of themselves is a good thing. This is the bigger picture, about a healthy nation.
But all those benefits are lost, if a blanket reliance on IVF becomes the norm. Frozen semen cannot be implanted back into a man's body or used in natural reproduction. That much is obvious.it can only be used for artificial insemination, seeding it mechanically into a woman's body, or in IVF.
We therefore risk an entire generation growing up, with the subconscious idea that artificial reproduction is the way of the future.
Other alarming questions pop up, almost too many to answer. Who will pay for this mass sperm freezing? How will young men be enrolled, and what of the enormous costs of storing so much biological matter safely and efficiently?
At the moment, it costs around £ 150-200 to freeze sperm with an additional fee for annual storage. It's hard to imagine many 18-year-olds signing up for that privately, so how much is it going to cost the NHS - and what other services might suffer as a result?
What about future treatments? Will they be guaranteed free on the NHS, for these men in 20 or 30 years' time? What are the ethical considerations if the men want to use their sperm much, much later in life? In other words, who has the ultimate control over the genetic content of those frozen samples?
I believe there is a better solution, and it certainly does not involve large-scale sperm banks for teenagers. We have to educate our way out of this crisis.
Better education enables both men and women to live healthier lives, and to make more informed choices about when to start trying for a family. Far too often I see women who have left it too late, who have been misled by the media and celebrity culture into thinking that they could postpone motherhood almost indefinitely. The hard truth is that they cannot.
We know that sex education in schools works. Teenage pregnancies have been significantly reduced by teaching young people the basics about contraception.
One of those basics is that natural fertility brings health benefits for everyone. We do not want to stumble blindly into a future where babies are made primarily by artificial procedures.
Let us use fertility education to promote natural fertility. It is in our nation's long-term interest.