There could be a link between birth control and a woman’s ability to secure and keep her selected partners. This link could lead to difficulty reproducing. With current birth control options, women have a large amount of control over their partner selection and fertility. Researchers, however, believe there could be a link between this control and a woman's ability to secure and keep her selected partners. This link could lead to difficulty reproducing.
Birth control pills regulate hormonal cycles in women. These pills are prescribed for pregnancy prevention, but also for regulating the monthly menses cycle. Doctors have found that the hormonal changes that occur when taking birth control pills may alter a woman's choice of partners.
When women take birth control pills, their bodies are essentially reacting as if it were pregnant for the majority of the month. This is not the same way a woman's body reacts to hormonal changes when she is not taking birth control. Evidence has been found that women prefer men who are genetically different from themselves during their ovulation period. When taking birth control, that ovulation period is altered due to the regulation of the natural hormones in the female body. Research has also noted that two people who are genetically different may have a better chance conceiving than a set of partners who are similar genetically.
Combine this with the fact that males can subconsciously detect an ovulating female with a stronger urge being felt toward women in natural ovulation and birth control could cause difficulty with two natural partners meeting up and staying together.
"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," suggests Dr. Virpi Lummaa, article reviewer.
The effect of the birth control pill could last for several generations. If females are less attracted to genetically different males, their chances of reproduction could be pronounced.
Source: Trends in Ecology and Evolution - October 2009