The “reproductive suppression hypothesis” states that the strong desire of adolescent girls in our culture to control their weight may reflect the operation of an adaptive mechanism by which ancestral women controlled the timing of their sexual maturation and hence first reproduction, in response to cues about the probable success of reproduction in the current situation. We develop a model based on this hypothesis and explore its behavior and evolutionary and psychological implications across a range of parameter values. We use (...) the process of model development to identify assumptions implicit in the reproductive suppression hypothesis and variables that need to be measured in order to investigate it more fully. In addition, because costs were probably associated with weight control, an important part of this analysis is the specification of situations in which the benefits of adaptive adjustment of the maturation schedule could have outweighed the costs of achieving that adjustment by slowing adolescent weight gain. (shrink)

We present a quantitative model of sex allocation to investigate whether the simple “rules of thumb” suggested by Trivers and Willard (1973) would really maximize numbers of grandchildren in human populations. Using demographic data from the !Kung of southern Africa and the basic assumptions of the Trivers-Willard hypothesis, we calculate expected numbers of grandchildren based on age- and sex-specific reproductive value. Patterns of parental investment that would maximize numbers of expected grandchildren often differ from the Trivers-Willard rules. In particular, the (...) optimum parental behavior is sensitive to population dynamics, type of parental investment, and, most important, relative ages of sons and daughters. It is doubtful whether a parent blindly following the simple Trivers-Willard rules would maximize numbers of expected grandchildren, on average. In addition, we show that sex-specific infanticide will almost never achieve the goal of maximizing expected numbers of grandchildren. (shrink)

A paper was published in 2003 discussing the ethics of nurses participating in executions by inserting the intravenous line for lethal injections and providing care until death. This paper was circulated on an international email list of senior nurses and academics to engender discussion. From that discussion, several people agreed to contribute to a paper expressing their own thoughts and feelings about the ethics of nurses participating in executions in countries where capital punishment is legal. While a range of opinions (...) were presented, these opinions fell into two main themes. The first of these included reflections on the philosophical obligations of nurses as caregivers who support those in times of great need, including condemned prisoners at the end of life. The second theme encompassed the notion that no nurse ever should participate in the active taking of life, in line with the codes of ethics of various nursing organisations. This range of opinions suggests the complexity of this issue and the need for further public discussion. (shrink)