The study of genes -- where they are, what they are, and what they do has never been easy. We know they occur on the chromosomes, but even that ostensibly straightforward fact was complicated in the early days.

How can this happen? How can Phil Dowd -- one of the English Premier League's most experienced referees -- make a call as atrociously bad as the one he made at the 34th minute of Saturday's Everton-Liverpool game?

Unthinkable is probably too strong a word, but the ignominious departure of the New York Red Bulls and the Seattle Sounders from the MLS playoffs certainly seemed to defy probability. Above all, the manner of their defeats, with the hammer-blow for each team coming via defeat in a climactic game in their home stadium jammed with their own frenetic, expectant fans.

'Tis the season, or postseason anyway, of playoff soccer. Whatever that means. The phrase gets repeated and repeated -- the TV guys love it, of course, without giving us any clear explanation of what they mean.

To his credit, PRO's Paul Rejer has not refused to deal with referee mistakes in his "Play of the Week" feature on PRO's website. They make up a minority of his cases -- for the simple reason that referees, by and large, get things right.