Childbirth Envy: Why Men Run Ultras

Dr. Blake P. Wood
Los Alamos National Laboratory
Los Alamos, NM 87545

Originally published in UltraRunning Magazine
Vol. 19, No. 4, September 1999


A new theory is advanced to account for the observation that participants in the sport of ultrarunning are overwhelmingly male. It is suggested that male ultrarunners suffer from "childbirth envy" - the subconscious desire to duplicate the painful experience of childbirth.


In the sport of ultrarunning (participation in foot races of distances longer than the standard 26 mile marathon) the great majority of participants are male. This is true in both road and trail ultras. For instance, of the 774 finishers of the 1998 John F. Kennedy 50 Mile Race, America's largest and oldest ultra, only 104 (13.4%) were female [1]. A review of the 1998 finishers of the 18 trail runs in the NM MTN RNR series shows that of 269 total finishes, 57 (21.1%) were by women [2]. Why is this? Anecdotal evidence suggests that this cannot be explained by lower finishing rates for women [3], in other words, the low participation rate is present at the starting line. Some researchers have suggested this low participation rate is the result of a societal bias against women in sports, which discourages participation in athletics from early childhood [4]. In this paper, we suggest a new theory to explain these observations: childbirth envy.

The Evidence for Childbirth Envy

The theory of childbirth envy can be stated simply: men have a subconscious desire to duplicate the painful experience of childbirth, and women, particularly those who have experienced childbirth, have no desire to repeat the experience. The evidence for this can be summarized as follows:

  1. The majority of women ultrarunners have not borne children.
  2. The ultrarunning phenomena of "fading memory" wherein runners swear at the completion of an ultra never to do it again, and then sign up for another a few days later, has a strong parallel in the rapid fading of the memory of pain in childbirth.
  3. The declining birthrate in the U.S. shows a strong correlation to the increasing number of woman ultrarunners, suggesting that, even among women, ultrarunning can be an emotional substitute for the experience of childbirth.
  4. Wives and mothers generally make excellent crew for ultras, by virtue of the empathy into the runner's physical and mental condition gained through the experience of childbirth.

We will now examine each of these points of evidence in more detail.

A review of the "ultrarunner profile" column of UltraRunning magazine over the past five years shows that, of 16 profiles of women ultrarunners (out of 46 profiles total), only six (37.5%) report having children. This is consistent with the 38.3% of women ultrarunners (of a sample of 128) responding to a recent survey who report having children [5]. In this same survey, only 20.3% of women ultrarunners report having children under the age of 16 - women who have "recently" given birth are apparently less likely to run ultras. These figures are significantly lower than the 56% of all women between the ages of 15 and 44 who have children, according to the U.S. Census Bureau [6]. These numbers strongly suggest that either ultrarunning discourages childbirth, or that the experience of childbirth discourages ultrarunning. Strengthening this point is the fact that no male ultrarunners (nor males in general) are known to have borne children [7].

It is well known that ultrarunners, upon finishing a race, commonly beg their friends to beat them silly, or pray to God to strike them dead, should they ever even think of running another ultra [8]. Almost without exception, these same runners will be found, within a few days, planning their next ultra. This rapid fading of memories of the pain of ultrarunning is remarkably similar to that which occurs following childbirth. For instance, one woman reported a memory of the existence of pain during childbirth, while claiming to have no strong memory of the pain itself [9]. Memory of the pain did not return until another childbirth, several years later [10]. This delayed return of strong memories of pain also is common in ultrarunning.

The birthrate in most western countries has been declining precipitously over the past 40 years [11]. Over the same period, ultrarunning has been growing, both in the number of races held and the number of ultrarunners participating [12]. This increase has been particularly pronounced among women. It has been suggested [13] that women, as well as men, find ultrarunning to be an emotional substitute for childbirth.

Paradoxically, although women who have experienced childbirth appear to shy away from participating in ultras, it is well known that they make excellent crew for their husbands, sons, and friends who do participate. The reason should be obvious: due to the similarities between the pain of running ultras and the pain of childbirth, women who have experienced the latter have an understanding of and empathy for the former [14]. At least one ultrarunner has gone so far as to declare "When you find a good crew, marry her!" [15] Others employ even more extreme methods to develop a good crew [16].

The Role of Ultrarunning in Human Evolution

Childbirth envy appears not to be a recent phenomenon. The running prowess of many Native American cultures, such as the Navajo and Tarahumara, suggests a long history of ultrarunning in human evolution. Evidence for this is presented in Figure 1, which shows a petroglyph, thought to date from around 1190 AD [17], of an ancient Anasazi ultrarunner.

A central figure in the mythology of the Anasazi, as well as some modern Native American cultures, is Kokopelli, the mischief making, flute playing, fertility icon shown in Figure 2(left). Recent research suggests that, in addition to these attributes, Kokopelli is intended to represent an ultrarunner. For comparison, Figure 2(right) shows a mischief making, modern ultrarunner. The similarities between them are obvious. Note that this particular ultrarunner clutches a cigar rather than a flute, which may fill a similar role in the fertility rite, as the cigar is often considered a sexual object among modern man [18]. Kokopelli is frequently depicted in petroglyphs as participating in explicit acts of copulation, and with greatly exaggerated genitalia [19]. For modesty sake, neither of these are depicted in Figure 2. In light of the long history of ultrarunning in human culture, one leading anthropologist [20] has suggested that the paradigm for development of the monogamous sexual relationship, "man the hunter, woman the child-raiser," should be replaced by "man the ultrarunner, woman the crew", hearkening back to the discussion in the previous section about the value placed by modern ultrarunners on a good crew.


In this paper, we have proposed a new theory of "childbirth envy" to explain why men run ultras. This theory is shown to be consistent with observations about the relative participation of women in ultras, the selective memory of painful events common to ultrarunning and childbirth, the apparent correlation between the declining birthrate and increasing participation in ultrarunning, and the value of wives and mothers as ultra crew. It is shown that ultrarunning has a long history, perhaps dating back to prehistoric times, and may have exerted a great influence on the course of human evolution.

About the author

Blake P. Wood is a staff physicist at Los Alamos National Laboratory. He completed his Ph.D. in electrical engineering at U.C. Berkeley in 1991. He has completed dozens of ultras, including the Hardrock Hundred (four times) and the Barkley 60 mile Fun Run (three times). He still thinks he can finish five loops at Barkley. He calculates that his total accumulated unpleasantness from running ultras adds up to about 1% of that endured by his wife in the course of producing three beautiful children. He has stated that "it would be interesting to be pregnant, maybe for an hour, tops."  

Figure 1. Petroglyph of an ancient Anasazi ultrarunner.

Figure 2.

Left: Kokopelli, the mischief making fertility icon of the Anasazi.

Right: Gary Cantrell, the mischief making modern ultrarunner and Barkley race director.


  1. G. Lindgren, UltraRunning Magazine, Vol. 18, No. 9, pp. 6-10, March 1999.
  2. Statistics compiled by Charlie Thorn, Los Alamos, NM 87544.
  3. At least, that's how it looks to me.
  4. I'm sure I read this somewhere, and can look it up if necessary.
  5. R. Trittipoe, UltraRunning Magazine, Vol. 17, No. 3, pp. 52-53, July-August 1997.
  6. A. Bachu, "Fertility of American Women: June 1994", U.S. Census Bureau Current Population Reports, Series P20-482.
  7. Personal communication, Dennis Mann, 3rd grade sex education, Mountain View Elementary School, Claremont, CA, 1966.
  8. "It would be better to smash my head in with that big rock." Anonymous Barkley runner, personal communication.
  9. "I know it must have hurt, because I remember screaming, but I don't remember any pain." Rebecca Clark, personal communication, 1983.
  10. "Darn you! Why didn't you remind me how much this hurts!!" Rebecca Clark, personal communication, 1986.
  11. US Census Bureau, Historical Statistics of the United States, General Printing Office, Washington, DC.
  12. When I ran my first marathon, in 1974, the race had about 900 participants, and at the time was one of the largest marathons. Nowadays, any big name marathon that attracted fewer than 1000 runners would be considered a failure, and fields up to 10 times that number are not uncommon.
  13. I suggested this to a co-worker just a couple days ago. He thought I was crazy.
  14. "I felt like you do 24 hours a day for nine months straight. Three times! If you're going to be sick, you might as well do it on the trail as in the aid station!", Rebecca Clark, personal communication during a 100 miler.
  15. Personal communication on the internet ultra list.
  16. My master plan for growing my own crew is nearing fruition. The oldest of my three daughters now has her driving learner's permit. Within a year, she should be fully trained and qualified to drive winding backroads in the dead of night to minister to my needs at remote aid stations. No doubt her value as crew would be enhanced by bearing a few children. I'm willing to wait a few years for this, however.
  17. Or was it 1990? I'll have to ask Cathy Leclaire, who I got it from.
  18. The Starr Report, Phil Kuntz, Ed., Pocket Books, New York, 1998.
  19. Dennis Slifer and James Duffield, Kokopelli: Fluteplayer Images in Rock Art, Ancient City Press, Santa Fe, NM, 1994.
  20. That would be me. I got an A+ in freshman Physical Anthropology in 1976 at U.C. Santa Barbara. I have also been the lead runner in many ultras. Get it??

© Blake P Wood, 1999.