China: 5000 years old and on the move.

Just got back from China, from Beijing and Hong Kong to be exact. I lectured to several medical and academic institutions on where I believe men’s health is headed in the future. What I found was an audience eager to push the research frontiers in this field, however I also a sensed a lack of sufficient infrastructure to do this at the highest level. I paused for a moment to think about what was possible, since a monumental tidal wave of increased industrial productivity and change is occurring in China. For example, there are 1000 new cars being put on the road daily in Beijing alone! I sensed that when the might of China’s intellectual potential directs its energy toward medical research and innovation, the world will stand in utter awe at the prodigious output that will result.

Despite the fact that China’s culture is endowed with 5000 years of evolution and is responsible for helping to define human civilization, one thing really surprised me: its decision in 1979 to control its population by mandating a “One Child Only” policy. In the rest of the world, human reproduction is a basic right and for the most part, entirely unregulated. Under China law, families are allowed to have one child. After that, a vasectomy is performed on the male partner. Like it or not.

In addition to great control of population growth, the “One Child Only” policy has also led to the development of the wildly successful “No Scalpel Vasectomy” procedure. Now relatively common in the U.S., the “No Scalpel Vasectomy” is a quicker (10 minute), cleaner, less invasive and more comfortable innovation on a 100-year old American procedure.

But the curse of the “No Scalpel Vasectomy” is now being felt in China. Currently, it is difficult to find enough youth to fill jobs in urban areas within the massive and burgeoning Chinese economy. As a consequence, there has been a softening of the law such that couples that are both products of “one child” parents can now have two children. So can farmers, handicapped couples, and couples who work in “high risk” occupations like coal mining, heavy equipment operations and the like.

Even more fascinating is that infertile couples have a real reproductive edge over fertile couples under this law. How? Well, if they need assisted reproduction to help them conceive and they happen to have twins or triplets as a result (a 30-40% chance), they are not penalized for bearing “extra” children. Can’t help but think that this little known fact may partly contribute to the size of the massive, bustling IVF clinics that I visited in China last week. many of which are 4-10 times the size of U.S. clinics.

Estrogens and the manly man.

There must be something in the air… or water. The Bolivian President Evo Morales recently asserted publicly that hormones found in mass-produced foods are “feminizing” men. Speaking about chicken in Bolivia, which he believes are “loaded with feminine hormones,” he suggested that when men eat chicken “they are diverted from their nature as men.” So, is this how metrosexuals came to be?

But wait, the Vatican commented on this issue a year earlier, although they blamed female hormones from birth control pills for the increased estrogens in ground water. Pedro Castellvi, writing in the Vatican newspaper L’Osservatore Romano in 2009, stated: “we have sufficient data to affirm that one of the reasons for the not insignificant rise in male infertility in the west, is the environmental contamination caused by the pill.” Actually, it’s not the birth control pill itself but the urine from women taking the pill.

In fact, to date, the urine of women taking birth control pills has been blamed for worsening sperm counts in men, the growth of female sex organs in male fish, breast growth in young men and the early onset of puberty in young girls. What next?

Can I add a little balance to this discussion? First of all, exactly what is happening to men in Bolivia such that the President is not happy with them? Are they more civilized and less disruptive? Second, male infertility is not necessarily increasing in the western world; it may even be true that men have lower sperm counts now than a generation ago not because they are less fertile but because women are more fertile. Third, estrogens are found everywhere in the environment including in many plants (phytoestrogens) such as soy and legumes, and are not produced exclusively from the urine of women. Fourth, the intersex conditions that have been reported in many animal species tend to be caused by a very specific exposure at a very specific time point during fetal development and have been linked to pesticides, bisphenol A, dioxins and other environmental contaminants (xenoestrogens). Fifth, did we somehow forget about the worldwide obesity epidemic in humans and the fact that fat converts male hormones to female hormones? Lastly, there is little evidence that substantially increasing a man’s estrogen levels as an adult will dramatically alter anything, except maybe waist size and color preferences. Where the truth lies in all of this is currently unknown, but it is hard for me as a urologist to see how women’s urine could be blamed for so much.

Bacchus is no longer a role model...

What you weigh affects how your sperm play. And your fertility. Overweight men tend to have lower semen volumes, less sperm and more oddly shaped sperm. The same is also true for men who are too thin. So, along with the many other health hazards associated with obesity, add poor semen quality to the list.

Obesity in both sexes is known to be associated with heart disease, diabetes, hypertension, and metabolic syndrome among other nasty conditions that can shorten your life. Typically, obesity is measured with BMI or body mass index, which looks at weight in relation to height. Not a perfect measure, but reasonably accurate. Using this tool, the ideal BMI for men (and women) is considered to be 20-25. A Danish study of 1600 men showed that overweight men with a BMI > 25 had a 22% lower sperm concentration compared with healthy weight men. Interestingly, a BMI of <20 was also associated with poor semen quality. For optimal sperm production, then, it helps to be not too fat and not too thin.

But what about fertility? Is it also affected by obesity? Yup. Another recent study showed that for every 20-pound increase in a man’s weight, there is a 10% increase in the chance of infertility. And this remained true when other factors that might influence the results were accounted for, including obesity status of the women, the man’s age, cigarette smoking, alcohol intake, and solvent and pesticide exposure. In addition, obesity was associated with infertility in both older and younger men.

So what is it about weight that influences men’s sperm production and fertility? One theory is that sex hormone metabolism is altered by changes in weight. Sex hormones are the “fuel” for the engine (testis) to make sperm. Obesity increases fat stores and fat converts male hormones (testosterone) into female hormones (estrogens). Too much estrogen in men is bad for sperm production. Another theory posits that normal 2-degree difference in testis temperature relative to the body is lost with obesity, as excessive fat provides too much insulation and results in overheating. On the other hand, when a man is too thin, he may take on a “catabolic” metabolic state. With a body in “starvation mode,” fertility is not the first thing on its mind and sperm production and fertility suffer.

So, is the epidemic of obesity the reason why sperm counts have been falling in Western countries over the last 50 years? Maybe. But this problem is unique in that it is utterly and entirely preventable. Eat well and in moderation, sleep well and treat your body like a temple. You used to it for your own health; now do it for the health of your future family.

Where are you? Green means high and red means low.

When a couple decides to have children, they rarely, if ever, contemplate the effect this has on the nation. But population scientists do. The effect that birth rates have on society is critical—as basic as knowing whether a nation is sustaining their population or not. But, trying to figure out if birth rates are going up or down is also complex, not unlike taking our temperature by feeling our foreheads.

A good barometer of birth rate assesses the average number of births per woman, and is generally noted by country. For a country to sustain its population in the future, the replacement rate is 2.1, or 2.1 births to every woman. What has occupied the minds of population scientists over the past 20 years is the fact that birth rates have dropped around the world, especially in Europe, but also in China and Japan. Interestingly, many countries in Africa do not have this problem, with birth rates well above 4. 

Also notable is the fact that in the past 20 years, the population of the world has dropped, falling an average of 1% per year. You can imagine how much this issue has occupied the minds of population scientists who seek to explain the phenomenon. Contributing factors include changing attitudes about family size, the cost of raising a child and the wider availability of contraceptives. The birth rate may also be dropping because child mortality on the whole has dropped. Or, because women who choose to have children later create a temporary lull in the birth rate. One concern with population drops is that countries whose populations become too small may not be able to afford to support its infrastructure, causing economic decline. So, on the one hand, it’s expensive to raise a child. On the other, it’s also expensive not to.

A recent study however, does show a change in these trends. Fertility rates now show a recent increase in developed nations. For years it has been thought that for some reason, developed nations, including most of Europe, have steadily dwindling populations. But this may not actually be the case. For example, in the 1970s, the US fertility rate was at a low of 1.74; lately it’s been relatively stable at 2.05. It appears that children are still wanted in a modernized world.

It’s quite hard to see these trends in my daily medical practice, as I perform as many vasectomies as I do vasectomy reversals. It’s even harder to render an opinion when the information is so diffuse and generational. So, to population scientist, I am a professionally “neutral contributor” to fertility rates. Like to think I do more good than that though…