Remember the opening to that 80s movie Look Who’s Talking? It features a whole bunch of sperm with clever dialogue racing to fertilize a largely inanimate egg. I remember being intrigued by that scene as a kid, but now it really bugs me that the sperm get to have full personalities and the egg doesn’t. It really mirrors medieval (and some modern) ideas of the woman/egg as just a reproductive vessel. Now, this fascinating story from Robert Martin (emeritus curator of biological anthropology at the Field Museum in Chicago) sheds some light on how popular-culture myths like the one showcased in Look Who’s Talking actually impact understandings of scientific processes. For example:
“Most notably, the legacy of the homunculus survives in the stubbornly persistent notion of the egg as a passive participant in fertilisation, awaiting the active sperm to swim through a hailstorm of challenges to perpetuate life. It’s understandable – though unfortunate – that a lay public might adopt these erroneous, sexist paradigms and metaphors. But biologists and physicians are guilty as well.”
The most interesting thing I learned in this article is that sperm are much more passive than we imagine–and the female reproductive tract as a whole is much more active: “most mammalian sperm do not in fact swim up the entire female tract but are passively transported part or most of the way by pumping and wafting motions of the womb and oviducts.”
(We could also construct this sentence in the active voice: “The womb and oviducts transport sperm most or part of the way to their destination with pumping and wafting motions.”)
Read the whole article here:
**My one quibble with this article is that it claims “Both IUI and IVF potentially increase the risk of polyspermy and the likelihood of miscarriage.” The article it cites as evidence (“Biology of Polyspermy in IVF and Its Clinical Indication” in Current Obstetrics and Gynecology Reports 2.4) actually suggests the opposite–that in vitro maturation results in a “lower polyspermic rate because of application of ICSI.” (ICSI is intraplasmic sperm injection, when an embryologist inserts a single sperm into an egg “by hand.”) The article states clearly that reasons for this correlation are unknown.