Germany has become Europe's first country to introduce a third gender by allowing babies born with characteristics of both sexes to be registered as neither male nor female.
The new law gives parents an option of leaving gender section blank on birth certificate, creating a category in public register for indeterminate sex.
The move is aimed at preventing parents from making a hasty decision about contoversial sex assignment surgeries for newborns, but critics say the law does not go far enough.
Lucie Veith, an intersex person from Hamburg told AFP news agency that the cosmetic genital surgeries for newborns must be forbidden altogether.
Veith said leaving the gender undefined on birth certificates was never the main lobbying point for her group, the German chapter of the Association of Intersexed People, or others in the intersex community.
Operations on intersex babies and infants take place in many European countries without informed consent by the patients, according to a 2012 European Commission report on the topic.
The Council of Europe addressed the issue for the first time last month in a Parliamentary Assembly resolution, calling on member states to study the prevalence of "non-medically justified operations" that may harm children and take steps to "ensure that no-one is subjected to unnecessary medical or surgical treatment that is cosmetic rather than vital for health during infancy or childhood".
The report also found that many adults born intersex are angry these surgeries were performed without their consent.
Experts estimate one in 1,500 to 2,000 births result in a baby of indeterminate gender or both male and female gender features.