Currently, if two men would like to raise a child together, they must either adopt a child or use an egg donor with only one of them being the surrogate. So, at most, only one of them can be the biological father.
A new paper published on Cell Press, a leading publisher of cutting-edge biomedical research and reviews, describes an immature cell becomes either a male or female cell and how the process can be manipulated. This means that is could be possible for stem cells from a man to be used to produce an egg. This egg could then be fertilizes by a second male in order to become a viable embryo that could be implanted into a woman. If such an embryo was brought to term the child would have the genetics from the two fathers and none from the woman who gave birth to the child.
There are many logistical and ethical concerns to be deal with before such a baby will be born. Many people are against the idea of genetic modification to create "designer babies". A social issue to overcome is those that are against homosexual couples from having children.
Recently, in the UK, a process called three-parent IVF has been approved. In the past this process has been used successfully to create living children that have DNS from three separate parents.