Peace
Quran & Sunnah
Does Islam explictly teach in official divine sources that same sex marriage is sin and prohibited?
Yes.
What happens if a man and women do not have children (family); does that make the marriage sinful or wrong in some sense according to Islam?
Not at all.
Is homosexual behavior and/or marriage unlawful in countries ruled by an Islamic government?
Yes.
Are you aware that creatures apart from humans does not follow the male and female senario that you posted in regards to reproduction?
How? Would you give me examples?