Humanity now stands before a great and unavoidable question — Do human beings face any natural limits?

The rise of new medical and biological technologies threatens to redefine what it means to be human, even as an ideological revolution has led many human beings to believe that we can effectively redefine ourselves as individuals.

We resist the idea that we are limited by age and its effects, and we call on medical science to assist our bodies to conform to our expectations.

This is glaringly apparent in the demand for access to reproductive technologies among women past the years of peak fertility. As so many women have moved into the marketplace, employment has taken the front seat as marriage and motherhood have been forced to move to the rear. Then, after spending their years of peak fertility in the workplace, many women decide that they want children after they reach the age of 40.

A British government agency reported yesterday that the number of women aged 40 and older seeking fertility treatments increased ten-fold over the past 15 years. As The Telegraph [London] reports:

The number of fresh IVF cycles carried out using patients’ own eggs among women aged 40-45 increased from 1991 to 2006, from 596 to 6,174. Statistics for women aged 40-45 as a proportion of all cycles among all ages increased from 10.7 per cent of all cycles in 2000 to 15.5 per cent in 2006, according to figures from the Human Fertilisation and Embryology Authority (HFEA).

Nevertheless, the British agency warned that success rates for women over 40 had not changed in that same period. As the paper explained:

However success rates are almost unchanged and fertility doctors yesterday warned women who wait until beyond their 30s that their chances of having a baby were much lower and the risks of medical complications far greater.  Angela McNab, the chief executive of the HFEA, said: “It is a matter of concern and it may well be that one of the messages we need to concentrate on is reminding women of the difficulties in achieving a pregnancy over 40 and certainly over 45.” Between 1991 and 1999 the proportion of IVF patients in this age bracket remained constant at around one in 10. Since then it has gradually climbed to 15.5 per cent last year.

The live birth rate as a result of treatment has remained almost unchanged for women aged 40, rising from 11.5 per cent in 1999 to 11.8 per cent in 2004 – the last year for which figures are available.

Another paper, The Times [London] framed its report this way:

Clare Brown, chief executive of the patient charity Infertility Network UK, said: “A lot of people don’t realise the very real effect of age on fertility. They look at people like Cherie Blair having babies in their forties, and think they’ll be fine, or that IVF is there as back-up. I don’t think many people are aware of the very low success rates of IVF at that age.”

Between 40 and 42, the live birthrate for a first treatment cycle is 9 per cent, at 43 or 44 it is 3 per cent, and at 44 or above it is 1 per cent.

Fertility treatment also becomes more hazardous with advancing maternal age. At 40, the risk of miscarriage is twice what it is at 20, and there is an increased likelihood of ectopic pregnancy, premature birth, stillbirth, neonatal death and birth defects. Pregnancy complications are also more common, as are Caesarean sections.

In other words, age matters. Of course, this would come as no surprise to those who lived in times past, when humans understood natural limitations on functions such as fertility.  Only in more recent times have humans demanded — and even come to expect — the ability to transcend these limitations.

Many women suffer under the illusion that they can postpone motherhood until their 40s or even beyond, and some go so far as to argue that a woman must have a right to set her own reproductive timetable, even if that means guaranteed access to expensive fertility technologies.

What these new reports make clear is that access does not mean success when it comes to these treatments and technologies.  Once again we confront natural limits.

A woman’s peak years of fertility and childbearing run from the late teens to her early 30s.  Enhanced health, nutrition, and modern obstetric care may explain why that period expanded into the 30s over the last century, but that expansion obviously had limits.

In the United States, the average age of first marriage for a woman is over 26 — already well into her years of peak fertility.  Add to that the impact of the contraceptive revolution and the fact that most of these women delay childbearing even further.

To a considerable extent, the fertility crisis for women is a crisis of delayed marriage and delayed motherhood.  Women have been sold a lie — that they can have it all.  The hard reality is that none of us, male or female, can have it all.  Scientists have recently discovered that male fertility also declines with age [see this article].

For most modern Americans the delay of marriage and childbearing does not mean the delay of sexual activity, of course.  So the masses now consider sex to be a recreational activity perhaps followed by commitment, marriage, and children.  The collapse of social disapproval of premarital sex has had consequences related to everything from delayed marriage to cohabitation and infertility.

To be human is to be a limited creature — and Christians understand that those limitations are not the accidental byproducts of evolution.  To the contrary, these limitations represent the intentional will of the Creator.

Furthermore, these limitations are to teach us something we need to know.  Our bodies are meant to inform us of the purposes for which we were made. Among these purposes is reproduction and childrearing within the context of marriage.

Our bodies also inform us that the clock is ticking, and that we are temporal beings.  As the writer of Ecclesiastes explained so poetically, “For everything there is a season, and a time for every matter under heaven:  a time to be born, and a time to die; a time to plant, and a time to pluck up what is planted” [Ecclesiastes 3:1-2].

As these new reports indicate, scientists fear that women who count on the ability to have babies after age 40 will miss out on motherhood.  Years of advances in reproductive technologies have not resolved this problem.

But the problem is not merely medical, as problems almost never are.  An ideology of autonomous individualism, false confidence in medical technologies, and new habits of human living and human sexuality contribute to the problem.

For some, marriage is an institution to be avoided and children are a hobby  to be postponed.  If fertility problems arise, many of these same people assume that modern medicine will overcome the problem.

Then again . . . maybe not.