The law would be used when the abuse victim was between age seven and 13, according to the Alabama Political Reporter .
For children younger than seven, state representative Steve Hurst told the political website, there is already legislation in place barring those molesters from getting parole.
Lawyer Raymond Johnson told WIAT the measure could be seen as a violation of the Eighth Amendment, which prohibits cruel and unusual punishment, and predicted it would be challenged in court.
"They're going to claim that it is cruel and unusual punishment for someone who has served their time and for the rest of their life have to be castrated," he told the station.
But the bill's chief sponsor's position is that it would prevent other children from being hurt.
"They have marked this child for life and the punishment should fit the crime," Mr Hurst told WIAT.
"I had people call me in the past when I introduced it and said, don't you think this is inhumane?
"I asked them what's more inhumane than when you take a little infant child, and you sexually molest that infant child when the child cannot defend themselves or get away, and they have to go through all the things they have to go through? If you want to talk about inhumane, that's inhumane."
Some objections were framed around whether or not the measure would actually work, and even Mr Hurst acknowledged that it would not be 100 per cent effective.
"A molester is still going to molest," state representative Sam Jones said.
"Medication won't do it."
