Biparental care is observed in less than 10 % of mammals and are often associated to monogamous relationships or immature offspring.

Homosexual behaviour has always been considered a paradox from an evolutionary point of view because it does not produce offspring, but there are nuances to this.

The following text is a summary of the full text available in Spanish and Catalan. Anna Veiga is well known for her pioneer work in the field of in vitro fertilisation in Spain. She was the first test-tube baby's scientific «mother» in Spain in 1984. She

Social and cultural anthropology has studied reproduction from numerous viewpoints.