In kayak racing -- played solo or in teams of 2 or 4; at distances of 200m, 500m or 1000m -- the mean ratio between women's and men's records was .88. In track cycling, at short or endurance distances, women's records were 88 percent of men's.

Even in crew rowing -- a sport for 1, 2, 4 or 9 people, with two different forms of rowing and two different average weights -- the mean ratio from men's over women's world records was .90.

Hammerman looked at a total of 82 events in all, across six sports, and the difference between all of their records fell between .84 and .94:

Ira Hammerman

Does this tell us something about the genders?

When talking about world records, we're always talking about the most accomplished human specimens. These aren't ordinary men or women. To arrive at any lesson about the basic difference between the genders, you have to jump a little, from the best to all.

And there could be social factors that shrink the available pool of women out of which the best athletes can emerge. In the US, let alone in other areas of the world, women make up only 41 percent of high school athletes.

At the same time, the 10 percent difference is clear from sport to sport and does not appear to be closely correlated with overall women's participation rates in athletics. Regardless of specifics, the factors which separate men and women probably seem to be, in Hammerman's words, "simple and basic."

Taking a kind of wild shot at which biological factors might affect athletic performance, Hammerman looked at hemoglobin counts and the maximum amount of oxygen an athlete can use in a minute.

And guess what he found? Men have an average of 13.6 to 17.5 grams of hemoglobin per decalliter in their blood. Women have 12.0 to 15.5 g/dl.

The ratio? .88 to .89.

And while maximum oxygen consumption statistics are harder to measure and harder to come by, if you compare them for four accomplished long distance runners of each gender, they average to 72.7 for women and 82.1 for men. 72.7 is about 89 percent of 82.1.

So, will women ever catch up to men?

There are two possible answers to this question. The most obvious interpretation is that no, women are not catching up to men. The data is converging on this ratio: in every sport that can be measured this way, the peak performance of the world's best female athletes tops out at around 90 percent of the peak performance of the world's best male athletes. In the 100m dash, by Hammerman's charting, this rough ratio has held for 55 years:

And this trend has held for decades in most sports.

The second answer is that women have already caught up to men. Women today, for example, swim as fast as men did forty years ago. The women's world record for butterfly ties Mark Spitz's 1967 record.