no good mon
It is nothing more than protein. It will not cause you harm.
If you swallow your own semen, then no, you can't get anything new. It's quite safe. It's fairly safe, too, to swallow someone else's semen.
No. When you swallow the semen, it goes to stomach and digested. Sputum comes from your lungs.
Infectious diseases can be transmitted for semen so swallowing semen is not consistent with "safe sex". Other than that there is nothing particularly good or bad about it.
yes
The same as anything else you digest
It's neither good or bad. Just like swallow semen for a woman.
if you want
YES! You can get Hepatitis by swallowing semen. You can also get AIDS/HIV.
you can swallow the semen. yes, some people do it because it is a "turn on".
Clearly, yes.