Are the parents of EU blue card holder eligible for family reunion Visa?
score:2
Accepted answer
ยง36 AufenthG says that an Aufenthaltserlaubnis may be granted to parents of a resident in Germany if not doing so would be an undue hardship. ยง36 ("kann", "may") is much weaker language than e.g. ยง30 ("ist ... zu erteilen", "shall be granted").
There are special rules when the resident in Germany is a minor refugee without any other guardian in Germany. Presumably a blue card holder is older than that.