Do Men Really Have a Biological Clock?

The fertility issues facing men and women still have profoundly different implications

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Steve Martin earlier this year. Martin became a first time father recently at the age of 67.

The news that autism and schizophrenia may be related to paternal age has brought mixed feeling to the legions of women who have long been warned about the dangers of trying to have children too late. Finally, it seems that the imperative to reproduce sooner rather than later will fall on prospective fathers as well as mothers. But calling this new awareness of the health risks of paternal age a ‘biological clock’ is somewhat misleading as the issues men and women face have profoundly different implications (for more, read Jeffrey Kluger’s story in the new issue of TIME, available to subscribers here).

The term originally had nothing to do with fertility. In the medical literature, it referred to the mysterious mechanism behind recurrent biological changes—daily shifts in body temperature, for example—and applied to men, women and amoebas alike. But during the 1970s, as women began flooding the work force, it began to be used—often by men—as the temporal waning of a woman’s ability to conceive, the force that ends ovulation and brings on menopause.  “The clock is ticking for the career woman,” warned Richard Cohen in the Washington Post in 1978.

(MORECan You Afford to Start Parenting at Middle Age?)

Today the biological clock refers to the drop off in female fertility after the age of 35, a decline that can begin even earlier. According to the American Congress of Obstetricians and Gynecologists (ACOG), “age is a significant factor influencing women’s ability to conceive.” A classic study of artificial insemination showed that after 12 cycles, 74% of women younger than 31 became pregnant, compared to 54% of women more than 35 years old. Moreover, when older women do get pregnant, the chance of having a miscarriage rises dramatically.

Although a woman’s risk of bearing a child with a disorder like Trisomy 21 (Down’s Syndrome) also rises after the age of 35, the biological clock really refers to whether she can conceive at all. (The fact that the cut-off point varies from woman to woman only brings more uncertainty and anxiety.) For men, the calculus is different. Although waiting longer may slightly increase the risk of having a child with a disease caused by a genetic mutation in the sperm, the overwhelming majority of their children will be healthy. The question then, for the older man, is not whether he can have children, but whether he should.

(MOREYahoo’s Work-at-Home Ban: Why It’s a Working Dad Issue, Too)

But here’s the problem. We rarely, if ever, tell older woman that they shouldn’t try to conceive. Instead we offer them genetic testing and the opportunity to terminate in the face of genetic anomalies, if they wish. We downplay the additional health risks to the child. In that sense, suggesting that older fathers shouldn’t have children would present something of a double standard.

Perhaps instead we should be looking at our insistence on unnatural fertility. We are the only species that delays reproduction beyond the onset of sexual maturity. It is our unnatural desire to postpone childbearing by decades, while searching for the right partner or establishing a chosen career, that has led to the dilemmas facing older parents — both men and women. The solution to our dilemma may be at hand: while we can’t stop getting older, we can be sure our sperm and eggs never do by freezing them for future use. In that case, the slow ticking of the biological clock may soon be a thing of the past.

MORE: “Too Old To Be A Dad?” by Jeffrey Kluger


From non-religious AAAS Biology...: 

Learn-Update Sleep, Genetics, Some Brain Disorders.


Identical Twins

Gene activity in the brain suggests that circadian rhythms are off-kilter in people with depression.


Re-Comprehend Sleep

Genes are life’s primal organisms, evolved from RNA nucleotides by the ubiquitous natural selection. Originally they were active ONLY during daylight time, at the pre bio-metabolism era.

Thus sleep is innate for all organisms, including for the genomes, which are the template organisms evolved by the RNAs for their own survival activities, as all life evolves for the purpose of supporting the RNAs survival.

The most essential energy requirements for organisms is for the daily housecleaning of their neural system centers. As bio-metabolism evolved it furnished indirect energy for this purpose, enabling adaptable flexible sleep times for the organisms.

Learn/re-comprehend sleep…

Dov Henis (comments from 22nd century)




5. Natural Selection is a trait of organisms, life?

No. Natural selection is ubiquitous for ALL mass formats, all spin arrays. It derives from the expansion of the universe. All mass formats, regardless of size and type, from black holes to the smallest particles, strive to increase their constrained energy in attempt to postpone their own reconversion to energy, to the energy that fuels cosmic expansion.

6. Life is an enigma?

Life is just another type of mass array, a self-replicating mass array. Earth life is a replicating RNAs mass. It has always been and still is an RNA world. ALL Earth’s organisms are evolved RNAs, evolved for maintaining-enhancing Earth’s biosphere, for prolonging RNAs survival.

7. Cells are Earth-life’s primal organisms?

NO. Earth’s life day one was the day on which RNA began replicating. RNAs, genes, are ORGANISMS. And so are their evolved templates, (RNA and DNA) genomes, ORGANISMS, as evidenced by life’s chirality and by life’s sleep.

8. Circadian Schmircadian sleep origin?

Sleep is inherent for life via the RNAs, the primal Earth ORGANISMS originated and originally active only under direct sunlight, in their pre-biometabolism genesis era.

9. Epigenetics are heritable gene functions changes not involving changes in DNA sequence?

The “heritable or enduring changes” are epiDNAtics, not epigenetics. Alternative splicing is not epigenetics, even if/when not involving alteration of the DNA sequence. Earth life is an RNA world.

10.Genetics drive biology and culture modifications?

NO. It is culture that modifies genetics, not genetics that modifies culture. Culture modifies genetics simply via the evolutionary natural selection process of the RNA ORGANISMS. Likewise many natural genetic changes are due to aging and/or circumstantial effects on the genes and/or genomes ORGANISMS, similar to aging and/or evolutionary processes in monocell communities or in multicelled organisms.


Dov Henis (Comments From 22nd Century)

Seed of Human-Chimp Genomes Diversity

Universe-Energy-Mass-Life Compilation


The content of this article is important to explore the possible unintended consequences of starting a family late in life. My own father was 72 years old when I was born and was 35 years older than my mother. I am happy to report that someone can have a perfectly normal life without the side effect results that are discussed in this Time Magazine article. At 54 years old I hold an executive level position with a multi-national training firm. I attained my masters in psychology at the age of 40 graduating with honors. My two teenage sons are honor roll students preparing for merit scholarships as they finish high school.

I would reach out to anyone considering having children in their sixties or seventies. Most people start a family with the intention to pass on more than their genetics. Knowingly giving life to someone who you will never have a parental relationship with is an interesting decision. Although the alternative of never being born is something the child would not want to choose, you also leave that person wondering about the amount of commitment the parent really had to the relationship. The older parent completes a life well lived and leaves someone who spends a lifetime thinking of what could have been.


Somebody explain to me why 90% of women are butt ugly.  Somebody still keeps doing them, I guess, but shouldn't they have been "phased-out" by now?


"For men, the calculus is different. Although waiting longer may slightly increase the risk of having a child with a disease caused by a genetic mutation in the sperm, the overwhelming majority of their children will be healthy."

Isn't there also a problem of micro-mutations in sperm DNA which accumulate in a man's life and which may not affect the basic health of a child conceived when the man is over the age of 35 or affect whether that child can reproduce?   These micromutations are nonetheless handed down through the generations in permanently damaged form and thus can present problems that are latent in one generation but cause more serious issues in later generations.  These damaged genes also become part of the human genome and in combination with other damaged genes may have compounding effects of problems for children.

This is why population geneticist James Crow said  something along the lines of "aging fertile men are the biggest modern threat to the human genome".