Under current state law, Washington couples wishing to have children via surrogacy are often forced to pay a woman under the table or go out of state to find one willing to carry their child.
But a measure by Democrat Rep. Jamie Pedersen of Seattle would make compensated surrogacy legal. The bill establishes a host of protections to ensure contracts would be made with informed consent and safeguards for both the birthmother and intended parents.
After contentious debate, the bill was approved in the House earlier this month. A committee hearing in the Senate is scheduled for Tuesday.
Supporters say the bill would make starting a family legally easier for same-sex and heterosexual couples.
But conservative faith-based groups say the measure would encourage the "sale of babies." They also oppose adoption of children by gay couples.