This diversity, as well as cultural practices and human consciousness, have all led to a large amount of variation in mating systems.
According to Bateman's principle of Lifespan Reproductive Success (LRS), human females display the least variance of the two sexes in their LRS due to their high obligatory parental investment, that is a nine-month gestational period, as well as lactation following birth in order to feed offspring so that their brain can grow to the required size.
[5] However, many other traits exist that may act as cues towards a man's ability to provide resources that have been sexually selected for in women's evolutionary history.
Additionally, the costs associated with an emotionally unstable partner such as jealousy and manipulation may outweigh the benefits associated with the resources they are able to provide.
[6] When finding a short-term mate, males highly value women with sexual experience and physical attractiveness.
[7] Men seeking short-term sexual relationships are likely to avoid women who are interested in commitment or require investment.
[8] Unlike many animals, humans are not able to consciously display physical changes to their body when they are ready to mate, so they have to rely on other forms of communication before engaging in a consensual relationship.
The initial research on the Hamilton–Zuk hypothesis[14] (see indicator traits) showed that, within one species (brightly colored birds), there was greater sexual selection for males that had brighter plumage (feathers).
[15] In cultures where parasitic infection is especially high, members could use cues available to them to determine the physical health status of the potential mate.
The genes of the MHC complex have extremely high variability, assumed to be a result of frequency-dependent parasite-driven selection and mate choice.
[29] Research completed on a Southern Brazilian student population resulted in similar findings that found significant differences in the attraction ratings of giving to male sweat and MHC-difference.
By using the larger data set to conduct analysis on 30 couples of European descent, they generate findings contrary to previous studies that identified significant divergence in the mate choice with accordance to HLA genotyping.