"Don't you think that even a VIP's son, be it of the Chief Minister or anybody else, also have a heart which beats," Yadav said.
"Relationship between a man and woman based on mutual consent is valid," he said addressing an election meeting for the assembly by-elections.
Suggesting that media stop prying into the private lives of politicians, Yadav said, he had also defended Congress General Secretary Digvijay Singh when his relationship with a woman journalist had become a matter of public debate.
Last week, Manjhi's son accompanied by a policewoman had allegedly flouted his father's position and asked a hotel in Gaya to give them a deluxe suite.
Fed up with meeting such demands from Manjhi's son, hotel employees locked the two inside the suite and raised an alarm.
The son coughed up cash to secure his release and that of his companion.
With the opposition BJP trying to make an issue of it, Manjhi had defended his son saying anybody could have a girl friend.