Don’t panic about sperm counts

Waikato Times Weekend - - WAIKATO WEEKEND - GWYNNE DYER

Among the many va­ri­eties of end-ofthe-world sto­ries we like to tell our­selves, the in­fer­til­ity apoc­a­lypse is the least vi­o­lent, and there­fore (in good hands) the most in­ter­est­ing in hu­man terms.

‘‘I tried count­ing mine once, but I went blind with ex­haus­tion,’’ tweeted one reader of the BBC web­site af­ter it re­ported that sperm counts were down by half in the past 40 years all over the de­vel­oped world. And it’s true: they are hard to count. The lit­tle bug­gers just won’t stay still.

The re­port, pub­lished by Hu­man Re­pro­duc­tion Up­date on Tues­day, is the work of Is­raeli, Amer­i­can, Dan­ish, Span­ish and Brazil­ian re­searchers, who re­viewed al­most 200 stud­ies done in var­i­ous places and times since 1973. It’s called ‘‘Tem­po­ral trends in sperm count: a sys­tem­atic re­view and metare­gres­sion anal­y­sis’’, and the au­thors are work­ing very hard to get the world’s at­ten­tion.

Dr Ha­gai Levine, the lead re­searcher, told the BBC that if the trend con­tin­ued, hu­mans would be­come ex­tinct.

‘‘If we will not change the ways that we are liv­ing and the en­vi­ron­ment and the chem­i­cals that we are ex­posed to, I am very wor­ried about what will hap­pen in the fu­ture,’’ he said. ‘‘Even­tu­ally we may have a prob­lem with re­pro­duc­tion in gen­eral, and it may be the ex­tinc­tion of the hu­man species.’’

I think I’ve seen this movie a few times al­ready. There was Chil­dren of Men, and then The Hand­maid’s Tale, and I was even in a sperm-count movie my­self 30 years ago. (It was a would-be com­edy called The Last Straw, but hap­pily it isn’t avail­able on­line.)

Among the many va­ri­eties of end-ofthe-world sto­ries we like to tell our­selves, the in­fer­til­ity apoc­a­lypse is the least vi­o­lent, and there­fore (in good hands) the most in­ter­est­ing in hu­man terms.

But the sperm cri­sis re­ally isn’t here yet, or even loom­ing on the hori­zon.

What the sci­en­tists did in the metare­gres­sion anal­y­sis was very use­ful from a gen­eral pub­lic health point of view. There have been many es­ti­mates of what is hap­pen­ing to sperm counts, but they are con­ducted un­der dif­fer­ent cir­cum­stances, usu­ally with fairly small groups of peo­ple, and of­ten in clin­ics that are treat­ing cou­ples with in­fer­til­ity prob­lems.

This big re­view of the ex­ist­ing re­search did no new work, but it did ex­tract rather more re­li­able data from the many stud­ies that have been con­ducted by other groups, and there def­i­nitely is some­thing go­ing on. Com­pared to 1970s, sperm counts now in the pre­dom­i­nantly white de­vel­oped coun­tries (North Amer­ica, Europe, Aus­tralia and New Zealand) are be­tween 50 and 60 per cent down now.

It has been a fairly steady de­cline in those places, and it is con­tin­u­ing in the present, but no such fall has been found in the sperm counts in South Amer­ica, Africa and Asia. So maybe it’s just whites go­ing ex­tinct.

Prob­a­bly not, though. Most peo­ple in South Amer­ica are white, but there has been no fall in sperm counts there. And there’s no sep­a­rate data in the sur­vey about what’s hap­pen­ing in the heav­ily in­dus­tri­alised Asian con­sumer so­ci­eties like Ja­pan, Korea, China and Tai­wan, but one sus­pects that there have been de­clines in sperm counts there. It’s al­most cer­tainly an en­vi­ron­men­tal, di­etary or life­style ef­fect, and there­fore prob­a­bly re­versible.

As to which of these pos­si­ble causes it might be, the jury is still out, but a 2012 study by re­searchers at the uni­ver­si­ties of Sh­effield and

Manch­ester con­cluded that smok­ing, drink­ing al­co­hol, recre­ational drug use and obe­sity had lit­tle or no ef­fect on sperm counts.

Other re­ports, how­ever, have sug­gested that eat­ing sat­u­rated fats, rid­ing bi­cy­cles, watch­ing too much tele­vi­sion and wear­ing tight underpants do ad­versely ef­fect sperm counts.

In any case, there’s no im­me­di­ate cause for panic, be­cause all of the stud­ies showed that sperm counts, though lower than in the 1970s in some parts of the world, are not ‘‘sub-fer­tile’’ any­where. They are still well within the nor­mal range, just lower on av­er­age than they used to be. There’s no short­age of hu­man be­ings at present, and there’s lots of time to sort this out.

It will al­most cer­tainly turn out, when more re­search has been done, that the main cause of re­duced sperm counts is the pres­ence of var­i­ous man-made chem­i­cals in the en­vi­ron­ment. Not just one or two chem­i­cals, but more likely a cock­tail of dif­fer­ent ones that col­lec­tively im­pose a bur­den on the nor­mal func­tion­ing of hu­man me­tab­o­lism.

We are breath­ing and in­gest­ing a lot of tox­ins, and have been since shortly af­ter the rise of civil­i­sa­tion (lead-lined wa­ter pipes, etc).

The sheer vol­ume of vis­i­ble pol­lu­tants (par­tic­u­late mat­ter, etc) has prob­a­bly peaked and be­gun to de­cline in the most de­vel­oped coun­tries, but the va­ri­ety of new chem­i­cals in the en­vi­ron­ment con­tin­ues to rise.

Fur­ther nasty sur­prises prob­a­bly lie in wait for us.

Un­for­tu­nately, that’s the way hu­man be­ings work: ig­nore the prob­lem or put up with it un­til it be­comes un­bear­able, and only then do some­thing about it.

It’s a strat­egy that has served us well enough in the past, but will do us in­creas­ing dam­age as the prob­lems be­come more com­plex.

It’s very un­likely, how­ever, that fall­ing sperm counts will be the one that fi­nally gets us.

Gwynne Dyer is an in­de­pen­dent jour­nal­ist whose ar­ti­cles are pub­lished in 45 coun­tries.

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