“This has to be accepted, even if it's difficult for those affected,” Kauder told the daily Berliner Zeitung. “I don't think children wish to be raised by homosexual couples.”
He said the question of children's well-being should come before the desires of adults to become parents.
“It's not about whether the adults want to live as a happy family,” he said. “There's no right to have a child.”
Germany introduced "registered partnerships" for same-sex couples in 2001, but stopped short of granting them the full rights and privileges afforded to married heterosexual couples.
Homosexuals can legally adopt the children of their partners, but adopting an unrelated child as a couple is not currently allowed.
Germany's highest court ruled in August the unequal treatment of straight and gay partners when it comes to taxes and exemptions is unconstitutional.
Justice Minister Sabine Leutheusser-Scharrenberger said at the time that Merkel's centre-right coalition would work towards ironing out remaining disadvantages for same-sex registered couples. But Kauder's most recent comments highlight the ongoing discrepancy between the Christian Democrats and their junior coalition partners the Free Democrats on gay issues.