I read a quote today that really moved me inside. "On the one side, conservatives pointed to abortion, illegitimacy, and homosexuality as forces destroying the family. On the other, liberals cited domestic violence, economic insecurity, and inadequate public supports as the key problems afflicting the family." - Whitehead
Even though both sides make very good points in such conservatives are saying that abortion and homosexuality is destroying families is because they don't believe this things are morally correct. Having an abortion is killing another human being and homosexuality is a sin in the bible. Liberals say violence , and economic problems destroy families because these are common problems in households today which lead to divorce. The family is not economically stable or there is violence in the household so there is tension and anger in the house.
But their are weaknesses in the viewpoints. Abortion and homosexuality are sins but this may give a family a chance to raise a child in a better home. If a teenager gets pregnant at 18 they are not economically stable to raise a child. If they get an abortion and have a kid later on in life they will have a better home for their first child. If a person is happier with the same sex this means the environment will be more stable for a child to be in , so when they are ready they can adopt and have a good home for a needy child.
So in my opinion I have to agree more with the liberal side in that domestic violence and economic problems destroy more families than abortion or homosexuality.