Con Team (Homosexuality).-

Source 1: 
http://www.debatingeurope.eu/focus/arguments-gay-adoption/#.WTx8AGg1_IU

Facts:

Gay parenting runs fundamentally counter to many people’s religious views. Legalising it would offend cherished beliefs and further undermine the key role religion plays as a moral bedrock in society. Christian, Jewish and Islamic leaders have all spoken out against gay marriage.

Source 2:

http://www.frc.org/get.cfm?i=if04g01

Facts:
If same-sex civil marriage becomes common, most same-sex couples with children would be lesbian couples. 
This would mean that we would have yet more children being raised apart from fathers. Among other things, we know that fathers excel in reducing antisocial behavior and delinquency in boys and sexual activity in girls.

Source 3:

https://www.tfpstudentaction.org/blog/10-reasons-why-homosexual-marriage-is-harmful-and-must-be-opposed

Facts:

Calling something marriage does not make it marriage. Marriage has always been a covenant between a man and a woman which is by its nature ordered toward the procreation and education of children and the unity and wellbeing of the spouses.