What this paper is discussing is effectively growing a human infant in a 'bag'. Because that uterus being implanted into a male human has none of the connectivity that a female human has. Some connections to blood supply can be done, sure, but what part of the male body is then working to control building this embryo? Therefore a great deal of the components that an embryo needs to use to build itself must then be injected and it must be from either alternative sources (animal) or synthesised.
The ethical issue is not whether a male should have an implanted uterus, the ethical issue is growing a human in a bag.
Now, in the past, posters have attempted to have me deleted for using this blunt language. However, we need to strip this down to what it really is.
All the ethical discussion is going nowhere. Currently there are rather strict limitations to how long a human embryo can be grown for experimentation purposes before it has to be destroyed. Sure some embryos might be subject to gene alterations etc, there may be some interutero procedures done, but to be grown in a bag from conception to birth??? No, I don't believe it would ever pass the ethical standards panels.