The Creator made them male and female

Some Pharisees approached Jesus, and tested him, saying,
"Is it lawful for a man to divorce his wife for any cause whatever?"
He said in reply, "Have you not read that from the beginning
the Creator made them male and female and said,
For this reason a man shall leave his father and mother
and be joined to his wife, and the two shall become one flesh?
So they are no longer two, but one flesh.
Therefore, what God has joined together, man must not separate."
They said to him, "Then why did Moses command
that the man give the woman a bill of divorce and dismiss her?"
He said to them, "Because of the hardness of your hearts
Moses allowed you to divorce your wives,
but from the beginning it was not so.
I say to you, whoever divorces his wife
(unless the marriage is unlawful)
and marries another commits adultery."
His disciples said to him,
"If that is the case of a man with his wife,
it is better not to marry."
He answered, "Not all can accept this word,
but only those to whom that is granted.
Some are incapable of marriage because they were born so;
some, because they were made so by others;
some, because they have renounced marriage
for the sake of the Kingdom of heaven.
Whoever can accept this ought to accept it."
(Mt 19:3-12)