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Could birth control pills alter mate choices?

Oct. 7, 2009
Courtesy Cell Press
and World Science staff

Birth con­trol pills may al­ter wom­en’s abil­i­ties to choose, com­pete for and re­tain mates, a new re­port suggests.

The pa­per pub­lished on­line on Oct. 7 in the re­search jour­nal Trends in Ecol­o­gy and Ev­o­lu­tion re­views emerg­ing ev­i­dence that oral con­tra­cep­tives af­fect these ac­ti­vi­ties by dis­tort­ing nat­u­ral hor­mo­nal cy­cles.

Wom­en are fer­tile briefly dur­ing their men­stru­al cy­cle, just be­fore ovula­t­ion. Stud­ies have found that both sex­es’ part­ner pref­er­ences vary ac­cord­ing to pre­dict­a­ble hor­mo­nal fluctua­t­ions as­so­ci­at­ed with this cy­cle. Ovu­lat­ing wom­en pre­fer more mas­cu­line, dom­i­nant and com­pet­i­tive males, as well as males more ge­net­ic­ally un­like them­selves. Mean­while men, some stud­ies sug­gest, de­tect wom­en’s fer­til­ity sta­tus, pre­ferring ovu­lat­ing wom­en in situa­t­ions where they can com­pare dif­fer­ent wom­en’s attrac­tiveness.

Con­tra­cep­tive pills al­ter the hor­mo­nal fluctua­t­ions as­so­ci­at­ed men­stru­al cy­cles and es­sen­tially mim­ic the more steady hor­mo­nal con­di­tions as­so­ci­at­ed with preg­nan­cy, ac­cord­ing to re­search­ers. “Lit­tle ef­fort has been in­vested in un­der­stand­ing the con­se­quences” of this, said study au­thor Al­ex­an­dra Alvergne of the De­part­ment of An­i­mal and Plant Sci­ences at the Un­ivers­ity of Shef­field, U.K.

Alverne and col­league Virpi Lumma re­viewed re­cent stud­ies sug­gesting use of the pill dis­rupts wom­en’s varia­t­ion in mate pref­er­ences across their men­stru­al cy­cle. The au­thors spec­u­lat­ed that the use of the pill may al­so in­flu­ence a wom­an’s abil­ity to at­tract a mate by re­duc­ing attrac­tiveness to men.

In­ter­est­ing­, wom­en on the pill don’t show the ovula­t­ion-specific at­traction to ge­net­ic­ally un­like part­ners, said Lum­maa. “The ul­ti­mate out­stand­ing ev­o­lu­tion­ary ques­tion con­cerns wheth­er the use of oral con­tra­cep­tives when mak­ing mat­ing de­ci­sions can have long-term con­se­quenc­es on the abil­ity of cou­ples to re­pro­duce.”

Tak­en to­geth­er, a grow­ing num­ber of stud­ies sug­gest the pill is likely to af­fect mat­ing de­ci­sions and thus re­pro­duc­tion, she added. “If this is the case, pill use will have im­plica­t­ions for both cur­rent and fu­ture genera­t­ions, and we hope that our re­view will stim­u­late fur­ther re­search.”

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Birth control plls may alter women’s abilities to choose, compete for and retain mates, scientists say. A paper published online on Oct. 7 in the research journal Trends in Ecology and Evolution reviews emerging evidence that oral contraceptives affect these activities by distorting natural hormonal cycles. Women are fertile briefly during their menstrual cycle, just before ovulation. Studies have found that both sexes’ partner preferences vary according to predictable hormonal fluctuations associated with this cycle. Ovulating women prefer more masculine, dominant and competitive males, as well as males more genetically unlike themselves. Meanwhile men, some studies suggest, detect women’s fertility status, preferring ovulating women in situations where they can compare different women’s attractiveness. Contraceptive pills alter the hormonal fluctuations associated menstrual cycles and essentially mimic the more steady hormonal conditions associated with pregnancy, according to researchers. “Little effort has been invested in understanding the consequences” of this, said study author Alexandra Alvergne of the Department of Animal and Plant Sciences at the University of Sheffield, U.K. Alverne and colleague Virpi Lumma reviewed recent studies suggesting use of the pill disrupts women’s variation in mate preferences across their menstrual cycle. The authors speculated that the use of the pill may also influence a woman’s ability to attract a mate by reducing attractiveness to men. Interestingly, women on the pill don’t show the ovulation-specific attraction to genetically unlike partners, said Lummaa. “The ultimate outstanding evolutionary question concerns whether the use of oral contraceptives when making mating decisions can have long-term consequences on the ability of couples to reproduce.” Taken together, a growing number of studies suggest the pill is likely to affect mating decisions and thus reproduction, she added. “If this is the case, pill use will have implications for both current and future generations, and we hope that our review will stimulate further research.”