Most of the prominent characters in the Mahabharat have unusual birth stories.
Gangeya / Bhishma & Krushna – They are the only surviving sons after seven infanticides. Both were separated from their natural “parent(s)” soon after birth and returned during adolescence. It is surprising that king Shantanu trusted his wife to look after his own surviving son after she had killed his previous seven children.
Krushna was secretly raised by his foster parents as his own maternal uncle sought to kill him.
Matsyagandha / Satyavati – she is suppose to have been born from a fish, which accounted for her unusual body odour. The odour changed from fish to flowers after sage Parashar sired a son with nubile Matsyagandha.
Krupacharya and Kripi – were both found abandoned in the forest by king Shantanu. He brought them to the palace and raised them as in accordance with their merit. It was later claimed that the children were born when a forest dwelling sage’s semen fell on a clump weeds upon seeing an apsara !
Dronacharya was similarly born when sage Bharadwaja captured his semen in a gourd / vessel after seeing an apsara.
Maharishi Vyasa was born to Matsyagandha when sage Parashar fell in love with the nubile girl ferrying him across the river Yamuna. Being young and unmarried, Matsyagandha handed the child over to the genetic father and Vyasamuni was raised by his father. This is one of the rare occasions when after the illicit affair, the father is left holding the baby !
Dhritarastra, Pandu and Vidur were born as result of political expedience. Throne of Kurus needed an heir urgently, its youthful king having died leaving two young widows. Maharishi Vyasa was summoned as the only biological son of raj-mata Satyavati aka Matsyagandha, to sire children that could be born within nine months of the king’s death. This would mean that for the most part, people would presume them to be the children of the last king. Due to time constraint, raj-mata (queen mother) insisted the children had to be sired as soon as possible, leading to one being born blind and another rather pale (with either thalassemia or some such blood disorder). Third child was born when the royal queens substituted their maid for themselves.
Karna and the Pandavas – were born as
result of liaisons between humans and Devas – non-human / alien species. This often accounted for their
super-human abilities.
Karna was born to princess Kunti and Surya deva (Sun) while she was still unmarried. Karna was born with impenetrable skin. It is reasonable that for species living close to the sun, skin of that nature would be essential to avoid being scorched by the sun’s rays. She disposed this illegitimate son by sending him down river in a floating basket to shield herself from society’s strictures.
Later, when Pandu was unable to sire children, as his queens, Kunti and Madri used the sacred mantra to summon devas to sire three + two sons. Hence the sons of Kunti and Madri are born of Vedic Devas – Dharma (Yama), Vayu, Indra and the Ashwini twins.
Kaurava princes were born of queen Gandhari as a huge shapeless knot ! Maharishi Vyasa dissected this knot into 101 parts and grew them in 101 vessels to yield 100 princes and one princess.
Shikhandi was transsexual. Originally, Shikhandi was born female. In a foolish and desperate bid for a “male heir”, Drupad raised Shikhandi as a “prince”. Sadly, the deception went too far when Drupad married Shikhandi to satisfy his royal ego that he had a son ! When the fraud was inevitably discovered on the wedding night, Shikhandi went to the forest to commit suicide to avoid public humiliation and stop a war between the two states. A kind Gandharv took pity on the grieving princess and Shikhandi became a man. Because Shikhandi was transsexual, Kuru-vrudha Pitamaha Bhishna refused to fight him.
Drupadi and Drushtadhyuman were born from a yagna to avenge the defeat of Panchal king Drupada at the hand of his former friend Dronacharya !
As both of these are fully mature at culmination of the yagna, their birth is probably easier to explain as “national search for patriotic candidates who would restore the kingdom’s pride”. After Panchal’s defeat, a “Yagna for Unity” would have raised patriotic fervour in the kingdom and two of its brightest, most fiery youngsters could have put themselves forward as candidates to restore the kingdom to its former glory.
Adopted into royalty, the new prince would have been tasked to learn all he can to defeat Drona in a battle. New princess would have been tasked to forge marriage alliances with worthy warrior (princes) to help defeat Drona. She made Yadavas her “brothers of oath” and married the five Pandavas to forge a solid alliance that could defeat Drona.
Shishupal was born with multiple extra limbs. His deformed look scared everyone. According one version of the tale, it was Shri Krushna who helped rid him of these deformities.
Ashwashthama though born “normally”, neighed at birth like a horse – hence his name – he who neighs like a horse. He had a prominent and unusual crystalline perturbation on his head. He believed this rendered him immune to many human failings. Yet, as we can see from his life, he had a lot of failings including rage and cruelty.