In this chapter we explore the routes that link differences between the sexes to sexual selection. Why is sexual selection often stronger in one sex? Why is the choosier sex usually less sexually competitive? What is the relationship between sexual selection and parental care? We outline -key theoretical models that apply to most taxa and account for the origin and evolution of sexual differenc...

The bright colors of birds are often attributed to sexual selection on males, but in many species both sexes are colorful and it has been long debated whether sexual selection can also explain this variation. We show that most evolutionary transitions in color have been toward similar plumage in both sexes, and the color of both sexes (for example, bright or dull) was associated with indices of...

Early initiation of sexual intercourse has been associated with negative consequences, such as higher rates of unwanted pregnancy and HIV infection. This study examined the attitudes and behavior of rural Thai adolescent students aged 16 to 20 years from northern Thailand regarding sexual intercourse. Differences between participants who previously had sexual intercourse and those who had not w...

Aspects of one‟s sexual behaviors, such as expectations, frequency, and types of behaviors affect one‟s sexual satisfaction. The current study investigated both sexual and non-sexual variables associated with sexual satisfaction. Participants were asked to report the frequency of various specific sexual behaviors within their marital relationship, as well as non-sexual aspects of their lives su...

Objectives: Those men who have long been suffering from infertility and failed to get any treatment experience higher levels of depression, are less satisfied with their sex lives, and are far less healthy. Sexual dysfunction is a problem among infertile couples that can affect marital relationship and satisfaction. This study aimed to examine male infertility and its influence on women’s...

This article reviews the research literature on sexual fantasy, a central aspect of human sexual behavior. Topics include (a) gender similarities and differences in the incidence, frequency, and content of sexual fantasies and how they relate to sociocultural and sociobiological theories of sexual behavior; (b) the association between frequency or content of sexual fantasies and variables such ...

Sexual information seeking is an important element within human information behavior. Seeking sexually related information on the Internet takes many forms and channels, including chat rooms discussions, accessing Websites or searching Web search engines for sexual materials. The study of sexual Web queries provides insight into sexually-related information-seeking behavior, of value to Web use...

Much research has been conducted on ethnic differences in sexuality, but few studies have systematically assessed the importance of acculturation in sexual behavior. The present study assessed general differences in normative sexual practices in healthy Euro-American, Asian, and Hispanic populations, using measures of acculturation to analyze the relative effects of heritage and mainstream cult...

conclusions sexual activity in last week of pregnancy might be associated with the onset of labor. therefore, in the absence of complications in term pregnancy, sexual activity can be considered as a natural way to prevent post term pregnancy. background pregnancy is one of the most critical periods in women's lives. sexual relationships change in this period. monitoring of uterine contractions...

There are dramatic individual differences among adolescents in how and when they become sexually active adults, and early sexual activity is frequently cited as a cause of concern for scientists, policymakers, and the general public. Understanding the causes and developmental impact of adolescent sexual activity can be furthered by considering genes as a source of individual differences. Quanti...