Why do so many people find it difficult to have children? Millions of couples want to have a baby, but are sometimes thwarted by problems or delays.
The news regularly headlines controversial birth control methods and the tragedy of unwanted children, but infertility often takes a back seat.
In the reproductive game, there is only a 25% possibility each month for conception, and for some people the chances of getting pregnant seem remote and unattainable.
It is possible to increase that likelihood.
One of the main things to avoid while trying to get pregnant is stress.
It is nearly impossible for any of us to avoid all stress, but the factors can be controlled.
Stress dampens down the body's production of hormones which encourage fertility.
Seemingly impossible living situations, or unbearable pressure at work can be mitigated to some extent by regular exercise.
Exercise is vital not just because it improves physical appearance, but because it helps the body to prepare for the huge changes ahead.
Another stress-reliever advocated by many is acupuncture, and meditation.
Lifestyle choices can make an enormous difference in overall health as related to fertility.
It may be surprising to learn that as many as 20% of couples trying to have children fail to become pregnant during the first year.
Choosing to smoke, or using illegal and even over-the-counter drugs can have an obvious negative role.
Other factors are exposure to environmental chemicals and pesticides, and an unhealthy body weight.
Severely underweight individuals sometimes experience a complete shutdown of the reproductive system.
By contrast, obese people who lose only 10 pounds have actually increased the chances for pregnancy.
Maintaining mental and emotional health also plays a positive role.
Unrelenting anxiety and depression actually cause physical changes.
A woman who is disturbed over not getting pregnant may only make things worse by worrying.
The anxiety decreases hormonal levels, which in turn affects the quality and implantation of her eggs.
One leads to the other, and the cycle can be hard to break.
But lifestyle changes or stress-reducing habits are not a cure-all.
The most important single factor seems to be good timing.
For most women, about 14 days before the start of her period is when the ovulation has actually occurred, and the average cycle begins about every 28 days, with variations from about 23-35 days.
The egg can survive unfertilized for about 48 hours, while any sperm deposited can stay viable for two or three days.
What this means is that the most intensely fertile time is about 13-16 days before the next period is due to start.
If a couple has a healthy lifestyle and the timing is accurate, why isn't pregnancy automatic? There is no shortage advice on the best post-coital positions or movements to encourage a successful link between swimming sperm cells and the egg.
Women are told to lay on their back, or assume an upside down position.
Men are told to save up their sperm supply by not having sex until the optimum time.
But there really is no proof that any of this is a sure cure.
Happily, one of the most beneficial ways to increase the odds of having a baby is to have more sex, two or three times a week during a woman's cycle.
In the week when ovulation is scheduled, intercourse is recommended every other day.
But, even this rigorous routine is no guarantee of success.
The woman who uses absolutely no form or birth control, and has random, non-scheduled intercourse, has a surprisingly low 11% chance of conception.
Past the age of 30 the body begins its inherited pattern of aging.
This usually decreases the chances of getting pregnant fast.
A couple in this age bracket who wants children are usually advised to wait at least six months before requesting any fertility tests.
While women bear the focus in childbirth, statistics show that 40-50% of fertility problems are caused by men.
An appearance of virility does not necessarily mean fertility.
But, once physical problems are ruled out, it is very important to realize that pregnancy doesn't always follow a schedule.
The best advice still seems to be allow enough time, and to encourage the natural process often and enjoyably.