See this article out of New York:
In New York State, surrogacy contracts are illegal because they were, in the words of legislators in the 1990s, "equivalent to buying and selling children."
Buying and selling human beings, and engaging in contracts that expect the state to enforce power over the human beings as a result of the sale, are by definition slavery.
Remember that the 13th Amendment is worded to distinguish slavery from involuntary servitude. The drafters of that amendment clearly referred to slavery as something distinct from being forced to work against one's will. Slavery referred generally to the treatment of people as chattel for sale and exchange.
However, in the New York case described above, the judge has deemed that a gay husband can adopt his partner's biological children despite the fact that the children were conceived through a contract that is illegal. The children are slaves according to American law, and now, the state of New York is using gay marriage law to allow them to fall under contractual obligation to obey an adult who is not related to them, and whose only claim to them is that he is married to the owner who purchased them illegally.
The children are too young to consent to having been removed from a mother who sold them. They are being forced to "love" a father who bought them, violently removed them from their mother, and then went to the courts to force them into the power of someone who isn't related to them.
Until the children are "emancipated" (that's the literal term here), they will have no choice but to obey the commands of an adult who is not related to them. The unrelated adult can force them to mow lawns, ground them, forbid them from seeing friends, drag them to one church and ban them from another, and punish them. If the children run away, the police will return them to this unrelated man's power. If the two men divorce, the children will be forced to submit to a court order about which of them controls their lives--and they are still too young to have consented to any of this.
I am not hypothesizing or being hysterical here. Let's review:
New York State has defined the purchase of children as illegal.
The 13th Amendment supports New York's law.
Gay marriage has been used to undo the ban on purchase of children, which is by definition slavery according to the 13th Amendment.
Gay marriage has caused slavery to return to the United States and the nation's courts and lawyers are ignoring the 13th Amendment. We are failing as a society.