I really do not have an easy answer. I guess a big part of me has not figured out exactly why means could not be found to make Clark the biological father. Maybe his sperm will not naturally join with human, but why not artificially.
On the other hand, I guess for the purposes of this story I have to accept that won't work.
I have to go with Evelyn and say adoption is the better option. Especially as pointed out, if they try to pass the child off as their biological child people will have a high probability of thinking Lois was cheating on Clark.
Maybe the local adoption agency hates them, and they could not adopt in New Troy. However even there, there are probably multiple adoption agencies. However International adoptions are always an option. If Lois can avoid getting kidnapped for a year as editor, she can make adoption meetings work. It is all about priorities.
Of course I have to admit I do not worry too much about the issue here. I start with the religious view that a sentient being from another planet would be biologically compatible enough with an earth-human to reproduce, and expect things to work out. I know that is a cop out of the real issues, but it is what I figure the situation would really be.
