Protection of family diversity: marriage, civil and de facto unions (cohabitation, joined families); same-sex unions and / or marriage

The plaintiff in the main proceeding is the mother of a child born in April 1997 and looked after by her, whose father was not married to her. In 1998, he was ordered to pay the plaintiff alimony under § 1615l.2 of the Civil Code in the amount of DM 1230 per month until the child reached the age of three. In May 2001, the plaintiff gave birth to another illegitimate child by another man. The father of this child was ordered by the court to pay the plaintiff child support in the amount of 211 euros per month for the period from February 2002 to May 2004. 
In 2002, the plaintiff applied for legal aid for an intended action against the defendant for payment of care maintenance from February 2002 in the amount of EUR 451 per month, deducting the maintenance payment by the father of her child, who was born in 2001, when calculating the amount of maintenance. Both the local court and the higher regional court rejected the application for lack of prospects of success in view of the time limit in § 1615l.2 of the Civil Code. By order of February 4, 2004, the FCC reversed the decisions and referred the case back to the localcourt, since the constitutionality of § 1615l.2 Sentence 3 of the Civil Code could not be decided in summary legal aid proceedings. After granting legal aid, the district court dismissed the action, citing the constitutionality of § 1615l.2 BGB.
The plaintiff appealed against this decision. In 2004, the higher regional court suspended the proceedings and referred the question of the constitutionality of § 1615l.2 Sentence 3 BGB to the FCC for a decision.
The FCC held that the different regulation of the duration of the maintenance claim was not compatible with the requirement arising from Article 6.5 of the Basic Law that non-marital children must be provided with the same conditions for their bodily and emotional development as marital children. 
Article 6.5 of the Basic Law prohibits considering longer personal care to be appropriate in the case of legitimate children, since the need for attention is to be assessed independently of the child's marital status.
The unequal treatment was not justified by the children's different social situations since the actual living conditions of legitimate and illegitimate children differ only insignificantly.
The diversity of non-marital relationships did not affect the responsibility of legal parents towards the child under Article 6.2 of the Basic Law.
Nor was justification derived from the fact that only in the case of divorced spouses can marital solidarity continue to have a claim-creating effect. It is true that against the background of the special protection of marriage under Article 6.1 of the Basic Law it is not impossible to place a divorced parent in a better position under maintenance law, which also has an indirect effect on the children's situation in life. However, if the maintenance claim exists solely because of the care of the joint child, Article 6.5 of the Basic Law prohibits a different assessment. Neither the wording nor the history of the origins of § 1570 of the Civil Code indicate that the claim goes beyond the care of the child. 
Even a constitutionally broad interpretation of the "gross inequity" under § 1615l.2 Sentence 3 of the Civil Code cannot remedy the violation of Article 6.5 of the Basic Law.
An interpretation of the exception contained in § 1615l.2 Sentence 3 of the Civil Code as a rule and thus an adjustment to § 1570 of the Civil Code would exceed the limits of an interpretation in conformity with the constitution. By limiting maintenance to three years as a rule, § 1615l.2 Sentence 3 of the Civil Code does not violate the parental right protected by Article 6.2 of the Basic Law.