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Models intercorse

Joseph B. Stanford, David B. Time to pregnancy, typically defined as the number of menstrual cycles required to achieve a clinical pregnancy, is widely used as a measure of couple fecundity in epidemiologic studies. Time to pregnancy studies seldom utilize detailed data on the timing and frequency of sexual intercourse and the timing of ovulation.
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Joint modeling of intercourse behavior and human fecundability using structural equation models

Human fecundability is defined as the probability of conception during a menstrual cycle among couples at risk for pregnancy. It is highly relevant for understanding human reproduction and represents a series of highly interrelated and timed processes. The statistical literature has recognized the need to incorporate both biological and behavioral factors Barrett and Marshall, ; Dunson and Stanford, when modeling conception probabilities, given that intercourse during the fertile window is a necessary but not sufficient criterion for conception. The heterogeneity of behaviors such as the timing and frequency of intercourse in a menstrual cycle needs to be considered when estimating conception. Here we propose a joint model of intercourse behavior and human fecundability through a classic conception probability model and a structural equation model SEM to accommodate intercourse during the menstrual cycle. The SEM part of the proposed model allows the dependency between intercourse behaviors on consecutive days in a menstrual cycle to vary across days. Consequently, the proposed model can accommodate not only a broad variety of intercourse patterns and dependency structures but also general covariate effects.
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An "epidemic" model of sexual intercourse prevalences for black and white adolescents.

Metrics details. The need to tackle sexual health problems and promote positive sexual health has been acknowledged in Irish health policy. Self-complete questionnaire data were collected from schoolchildren aged 15—18 years as part of a broader examination of health behaviour and their context.
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Satisfactory sexual intercourse for couples lasts from 3 to 13 minutes, contrary to popular fantasy about the need for hours of sexual activity, according to a survey of U. Thirty-four, or 68 percent, of the group responded and rated a range of time amounts for sexual intercourse, from penetration of the vagina by the penis until ejaculation, that they considered adequate, desirable, too short and too long. The average therapists' responses defined the ranges of intercourse activity times: "adequate," from minutes; "desirable," from minutes; "too short" from minutes; and "too long" from minutes.
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