Implications of various fertility patterns in the Republic of Korea (ROK) are studied by computer simulation. These patterns include the factors: age of marriage, sex preference, abortion (induced), contraception and sterilisation. As a result of studying a large number of combinations of these factors, the following tentative conclusions, among others, are reached. If future cohorts of women in the ROK become limiters after two live births and marry according to an observed high level marriage distribution, at least two of the methods of birth control--abortion, contraception, and sterilisation--will have to be used extensively to yield a mean number of live births (MNLB) in these cohorts of the order 2-2. However, if these women marry later than the observed high level marriage distribution and, in addition, accept effective methods of contraception more widely and use them more effectively, then the MNLB experienced by these cohorts could move below 2-5 wihtout the extensive utilisation of abortion and sterilisation.