Fetal Onanism: A Surprising Scientific Debate

By Neuroskeptic | July 3, 2017 4:16 pm

The medical journal Prenatal Diagnosis recently played host to a vigorous debate over whether a male fetus was spotted engaging in masturbation on ultrasound.


The alleged case of antenatal autoeroticism was reported by Spanish gynecologists Vanesa Rodríguez Fernández and Carlos López Ramón y Cajal in September last year. Their paper was called In utero gratification behaviour in male fetus. Here’s the ultrasonic evidence of the act:


Rodríguez Fernández and López Ramón y Cajal wrote that “This is a very clear sexual behavior ‘in utero’ in the 32nd week of gestation”, speculating that the fetus may have been comforting himself by the behaviour.

However, not everyone was convinced by these claims. In March 2017, Prenatal Diagnosis published a rather scathing ‘Comment’ on Rodríguez Fernández and López Ramón y Cajal’s paper. The author of the critique was Israeli ultrasound expert Israel Meizner, and he pulled no punches:

Looking at Figure 1 presented in the letter, one would have to conclude that the authors have made one huge error in the interpretation of the pictures presented. Picture no. 1 in Figure 1 represents a grasped normal hand with five fingers. What the authors mark as foreskin is the normal index finger.

In picture no. 2 in Figure 1, one can see the flexed hand with five fingers. What the authors mark as meatus is the flexed index finger, a bit drawn backwards.

The normal penis and scrotum are clearly visible in this picture, appearing medially to the clenched hand. I have indicated real penile tip and scrotum on a photocopy of picture 2, enclosed herewith.

Meizner included a (rather grainy) figure with what he says is the “Real Penis” helpfully labelled in yellow – and it’s not in the fetus’s hand:


López Ramón y Cajal and Rodríguez Fernández didn’t take this criticism of their ultrasound interpretation skills lying down, however. In their Response to Meizner’s criticism, they indignently deny having made any anatomical errors:

We do not agree with your analysis; the image is a snapshot of an exploration that was performed over a period of 30 min. Typically, I work using two ultrasound machines and seven transducers (three-dimensional mechanical and electronic transducers).

The behavior reported in our study was observed and confirmed by several doctors over a period of time… I would be happy for you to visit my hospital and ultrasound lab to witness this.

According to López Ramón y Cajal and Rodríguez Fernández, it was in fact Meizner who made an anatomical blooper. What Meizner called the “Real Penis” was actually the umbilical cord, they say. They also point out that it was Meizner himself who published the first ever report on pre-natal self-pleasure, in 1987.

So who is right in this dispute? I’m not sure, but what does seem certain is that the fetal masturbation controversy ranks among such great scientific debates of the past as Huxley-Wilberforce, Bohr-Einstein, and Gould-Dawkins.

It’s also fair to say that life is never dull for 32-week old fetuses these days. If researchers aren’t peeping at their private moments, they’re shining lasers at them.

CATEGORIZED UNDER: funny, papers, select, Top Posts
  • smut clyde

    “Fully retracted foreskin”? It is never to early to start with prepuce hygiene.

    • https://www.youtube.com/playlist?list=UUwbGJwCdp96FKSLuWpMybxQ Lee Rudolph

      Has Ivan Oransky been notified?

  • cat

    Must be quite frustrating when subsequently put into diapers. That could explain a lot!

  • Andrew Worth

    Poor kid, you’d think in the womb was the one place you would have some privacy and not have the public judging you.

  • lump1

    This really sounds like the start of Ali G’s origin story. I hope that kid grows up to be awesome and brags about how he’d been spankin’ it since the second trimester.

    • Virginia Gina Cantone Spiegel


  • smut clyde

    Metzger has a point. If the appendage is indeed the fetal penis as in the Spanish interpretation, then the fetus has only three fingers on that hand and is presumably a cartoon character.

  • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

    antenatal autoeroticism” How many angels were dancing on the head of that pin?

    • http://blogs.discovermagazine.com/neuroskeptic/ Neuroskeptic

      Other phrases I considered: “embry-onanism” and “fetal fapping”.

      • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

        Onanological embyropenesis in pre-term scobblelotchers?

      • Rowan

        Jerkin’ it gestationally

        • http://blogs.discovermagazine.com/neuroskeptic/ Neuroskeptic

          beatin’ his gamete

  • Not_that_anyone_cares, but…


    ker! Toss


  • CL

    Don´t know much about ultrasound, but if this is indeed a series of pictures recorded in one session, it seems a bit curious that the frame rate (FR) and % (whatever that means) changes in image three from 3Hz and 45% to 2Hz and 37%.
    Anyone familiar with the Phillips ultrasound device out there that can explain?

  • Tom Harlander

    Somebody seems obsessed with sex, must be a virgin himself.

  • tommyt

    Poor kid’s going to be born blind.

    • 31007 – TANSTAAFL

      with hairy palms

  • GlobalThinkTank

    Exactly!! Geewiz; not even in pre-birth can anyone get any rights to real privacy. WFH?! : /

  • Virginia Gina Cantone Spiegel

    This is wonderful news! To see and understand that man wants to please himself from birth, is a beautiful gift from God. Thank you for your research and for sharing it.

  • Erik Bosma

    Good thing he didn’t have a twin sister in there. Otherwise he’d be coming out to handcuffs.

  • StarRiders

    Will his parents name him “Portnoy?” This kid’s a fast learner. I waited until I was 13, though once I got started I couldn’t stop.

    • https://www.youtube.com/playlist?list=UUwbGJwCdp96FKSLuWpMybxQ Lee Rudolph

      Will his parents name him “Portnoy?”

      Not entirely apposite unless the placenta’s gotten mixed up with the liver, in which case I doubt he’ll be successfully carried to term.

  • Jerrisue

    And the tragedy is, whatever that fetus is doing, it is conscious, and under current laws can be aborted and thrown into a trash can. And in Oregon and California, we taxpayers have to pay the cost of killing it so the mother doesn’t bear the burden. Maybe more of these pictures should be on the evening news, but of course, it won’t be. Doesn’t fit the narrative.

    • http://blogs.discovermagazine.com/neuroskeptic/ Neuroskeptic

      Even if the fetus is masturbating, there’s no reason to believe it is conscious of doing so. People are known to carry out masturbation, and other complex motor actions, while asleep, or even while having a seizure.

      • splashy79

        Yes, many motor functions can be done without any consciousness at all. Huge amounts of that are done with the part of the brain that is not about consciousness at all.

    • Menthol

      Yeah, abortions at 32 weeks happy oh so frequently. Why don’t you worry about an actual problem instead of your made-up atrocities?

  • Pingback: Scientists disagree over ultrasound images showing male foetus 'masturbating in womb' - UK News()

  • Pingback: Scientists disagree over ultrasound images showing male foetus 'masturbating in womb' – UK News()

  • Pingback: Scientists disagree over ultrasound images showing male foetus 'masturbating in womb' – FUN#BUZZ()

  • Pingback: Phrase Of The Day – Unsightly Mental Blemishes()



No brain. No gain.

About Neuroskeptic

Neuroskeptic is a British neuroscientist who takes a skeptical look at his own field, and beyond. His blog offers a look at the latest developments in neuroscience, psychiatry and psychology through a critical lens.


See More

@Neuro_Skeptic on Twitter


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Collapse bottom bar