Don't do it is right. Sure there are the legal ramifications but also think about the kid and what's best for him. Also can you really just not have any contact with him?
We can tell the original poster that he doesn't need to be the live sperm donor without debating whether anyone can pull this off successfully, but we can point out how he might want to factor in whether he is creating a good situation for the kid.
Of course it is possible for someone to be a great single mom. There are millions of them. The difference here is the mother is purposely creating a kid and not giving it a father. Very different situation. Sure maybe it could work out but I don't think he should purposely create the situation.
This isn't like going out and buying a car. The mother is creating a life.
A kid on my street's dad lives a few states away. Great kid. Makes good grades, does sports. Yet at the same time you can tell how much he misses having a dad. One time he told me he wished I was his dad. I can't imagine purposely putting a kid in that situation. Doesn't mean the mother can't be a great mother.
Now maybe his situation is different than yours would be because my neighbor actually knows his dad and has some of the abandonment issues, probably in his mind figures if he was more worthy his dad wouldn't have "abandoned" him and maybe your kid wouldn't have these issues to the same extent, but I hope you see this isn't some easy situation where you get your rocks off with no repercussions.
I had to laugh at the guy who said to say you'd do it and wear a condom the first 15 times.
Weird that you picked those two dogs as I have a mix of those two dogs. If he was breeding dogs, definitely go for it.