Proponents of same-sex marriage point out that “traditional” concepts of marriage in actuality have already undergone significant change. Polygamy has been prohibited, married women are no longer considered the property of their husbands, divorce is legal, contraception within wedlock is allowed, and anti-miscegenation laws forbidding interracial marriage have been eliminated in most modern societies. The fact that changes in the customs and protocols of marriage often occur gives rise to the argument that marriage is dynamic, and same-sex marriage is only the latest evolution of the institution.
Adoption by same-sex couples is legal in Guam, Andorra, Belgium, Canada, United Kingdom, Iceland, the Netherlands, Sweden, South Africa, and Spain. Denmark, Germany and Norway allow “stepchild–adoption” so that the partner in a civil union can adopt the natural (or sometimes even adopted) child of his partner. In the Republic of Ireland and some other countries, individual persons, whether heterosexual/homosexual, cohabiting/single may apply for adoption.
Some opponents of adoption by same-sex couples question whether same-sex households provide children with adequate gender roles. The underlying sentiment is that, without both male and female role models, children may develop in such a way that they are unable to fulfill traditional gender roles in future heterosexual relationships.