We would like you to assess the QUALITY of each of the following argument (discussing Gay Marriage) and determine if the argument is Valid or Invalid. A valid argument is clearly interpretable and either expresses an argument, or a premise or a conclusion that can be used in an argument for the topic of gay marriage. An invalid argument is a phrase that cannot be interpreted as an argument or not on the topic of gay marriage.

if we say that same-sex couples should have the right to marry each other, then any two consenting adults should have the legal right to marry each other.
Valid

Some changes allowed different people to marry (blacks and whites, for example), while others expanded the rights of married people (like Federal tax breaks).
Valid

Some of the social changes we have experienced over the last century have made biology less important and people's social roles in creating families more important.

Valid