Hijra or Kinnar are invited to weddings and during childbirth for blessings in India. It is believed that the blessings of transgender or third sex have special powers. The story of power of the blessings of Kinnar is associated with Lord Ram and his exile in the Ramayana.
When Lord Rama was exiled and left for forest, several citizens of Ayodhya followed him. There were Hijras among those that followed Sri Ram.
When he reached the forest edge, Bhagavan asked the citizens to go back to their respective homes. Many of them returned back to their homes.
When Bhagavan Sri Ram returned after 14 years he found that Hijras had not left the place. They waited at the border of Ayodhya for 14 years. They did not go back. They lived on the border waiting of Bhagavan Sri Ram.
Bhagavan was moved by the devotion of Kinnars and gave them the boon that their blessing will always be true and it will be fulfilled.
From that time onwards Hijras were invited during wedding and childbirth to get their blessings.
It is also believed that the curse of Hijras will create numerous problems in life. So people avoid making the kinnars angry.