German citizenship is attained at birth if at least one parent is German. If you are not married and only the father is a German national, the child only attains German citizenship if the father effectively recognizes his paternity according to German law.
German nationals born abroad on or after 1 January 2000 should note that any children of theirs born outside Germany will acquire German nationality only if the parents report the birth to the competent German mission abroad before the child's first birthday.
Information on applying for a passport and, where applicable, on acknowledgement of paternity is available at the German mission covering your place of residence.
German missions abroad: Countries A to Z