Tuesday, March 31, 2009

Why doctors aren't scientists


Derrick took this picture yesterday when he and Sylvia went outside to enjoy the wonderful weather. Of course, today, when I get to spend the day with Sylvia, it was rainy and miserable all day, and consequently I had no desire to spend time outside, soaking up the sunshine and taking cute pictures of my daughter. Oh well, perhaps next week. In any case I thought I'd start this post with a cute picture and my (tongue in cheek) grousing so those of you who don't want to read further don't have to.

The next part of this post isn't likely to be as cheerful.

I have a friend who has spent the last seven years trying to treat her infertility and, after all that time, has decided she's done with medical treatments and is going to adopt. I applaud her decision--I'd wondered for a while why she didn't have any children because she'd obviously be a very good mother, but never asked because it's not really my business. I hope the process goes smoothly and well for her. I'm quite sure she'll enjoy motherhood and the children she's blessed with will have excellent lives under her care and tutelage.

The internet is a wonderful, terrible tool that I sometimes (okay, frequently) use to distract myself. I am curious, but have a remarkably short attention span. So, after discussing my friend's infertility with her, I started looking stuff up on google scholar. One of the first papers I came across contained this graph:The three graphs show the concentration of sperm, the percentage of motile sperm, and percentage of sperm with normal morphology for populations of infertile men (white) and fertile men (black). Notice that the distributions for the first two sets of measurements (concentration and motility) are nearly identical for the infertile and fertile populations. There are minor differences between the fertile and infertile populations evident in morphology, but the similarity of that distribution as well means that realistically, you can't tell if an individual is fertile or infertile based on these measurements--assigning them to one population or another won't be possible in many, many cases. It does not inspire my confidence in the medical community that typically a measurement of the above features is what's used to determine whether a male is fertile or not. I am particularly not comforted by the final conclusion of the article, which claims,

...our data from a large group of couples with well-documented fertility or infertility provide clinical standards for semen measurements that may be useful for diagnosing male-factor infertility and for distinguishing between subfertile, indeterminate, and fertile ranges. These thresholds can be applied in clinical practice and research, provided that there is strict quality control.


In my estimation, their data show pretty conclusively there's no way to determine whether a man is fertile or infertile based on these observations. Makes me wonder how many other couples have spent years chasing after (potentially) the wrong cause of their infertility, convinced the man can't possibly be the problem.

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