The creation of umbilical cord blood (UCB) banks raises interesting medical, social, economic and ethical issues. This paper reviews the ethical problems specifically. In this respect, it evaluates: a) whether there are advantages to the use of UCB compared to bone marrow, b) whether or not it is ethical to create UCB banks, c) whether their creation is ethically acceptable in terms of their clinical usefulness or d) the use made of them for therapeutic purposes, and finally e) whether their creation is ethically justified from a cost/profitability point of view. We focus primarily on evaluating the ethical controversy between public and private banks, particularly on whether it is ethical to bank autologous blood in private UCB banks, on the basis of its limited possibilities for use by the cord blood donor. We can conclude that, from an ethical point of view, autologous blood banks have limited acceptance among specialised researchers, scientific societies and other public institutions. Therefore, we believe that it is ethically more acceptable to support the creation of public UCB banks for medical and social reasons and, above all, based on the principle of justice and human solidarity. Nevertheless, there is no definitive ethical argument why a couple, according to their autonomy and freedom, cannot bank their child's UCB in a private bank. An equally acceptable solution could be the creation of mixed banks, such as that proposed by the Virgin Health Bank or like the Spanish system where autologous samples can be stored in public banks but with the proviso that if at any time the stored sample is required by any person other than the donor, it would have to be given to them.