With the progress in reproductive technology and the modern transformation of marriage and family, the traditional mode of natural reproduction and child-bearing at home is undergoing obvious changes, which has brought about a series of complicated and sharp ethical problems. This thesis aims at a rudimentary analysis of the ethical problems concerning modern child-bearing. It is divided into three sections: Chapter 1 providing a theoretical basis for the whole thesis; the main body covering the content from Chapter 2 to Chapter 8; the conclusion.Chapter 1 discloses the fact that changes in modes of human reproduction because of the progress in reproductive technology, social transformation and cultural changes not only means the deconstruction of the system of natural reproduction, which rested on marriage and family and legal sexuality, but also means that of traditional natural reproduction ethics. Thereby a lot of new ethical issues have been aroused. These issues may be summed up from the perspective of reproduction ethics as the following species: (1) ethical issues as a result of controlling the number of reproduction; (2) ethical issues as a result of controlling the quality of reproduction; (3) ethical issues as a result of applying complimentary techniques of reproduction; (4) ethical issues as a result of asexual reproductive technology; (5) ethical issues as a result of the changes in social behaviors. This thesis holds that when we look into these ethical issues concerning modern reproduction, we may inevitably resort to the two ways of analyzing the concept of goodness and that of Tightness, but this is not enough to provide a complete and convincing answer to all the issues to support social and individual choices of reproduction. Our standpoint is to combine the two. ways of thinking to establish a theoretical system of analyzing the issue of reproduction in modern times.On the theoretical system the thesis analyzes such ethical issues as those of moderate reproduction, those of sex choice in reproduction, those of asexual reproduction, those of reproduction without marriage, those of select reproduction, those of reproductive compensation, etc.Moderate reproduction forms a contrast with over-reproduction and under-reproduction, both of which can do harm to the development of social economy. The growth of the world's population takes on the tendency of polarization. On the one hand, the so-called population explosion has brought about a 'population crisis'; on the other, the negative growth of population in advanced countries has caused a 'reproductive crisis'. Thus, to keep the growth of population within a reasonable scope and to bring human reproduction onto a way favorable for the development of economy and human civilization is to provide the basis and premise for controlling the number of reproduction from a moral point of view.Sex choice is the act of the agents of reproduction to choose the sex of the child that they are to bear. The choice is influenced both by individual inclinations and social factors; it is an act of natural reproduction adjusted by " an invisible hand" as well as an act controlled by artificial factors. That mankind has been able to make sex choices is a progress in reproduction from " having no choice" to technologically having free choice". Seen from an ethical point of view, the application of the technology of sex choice is of some positive significance; however, if people have an laissez-faire attitude towards this kind of choice, then it will threaten the sex structure of population, which will accordingly do harm to the society. Therefore, individualism should be replaced by communitarianism.No marriage and reproduction is a choice led astray from the mainstream of social life. From " much reproduction" to "less reproduction" then to " no marriage and reproduction", this process notonly marks a change in the mode of reproduction, but also marks a transformation in social culture. In a multicultural society, choosing to have no marriage and no repr