The rules, legality, and guidelines around surrogacy, and who can become a gestational carrier, vary extensively by region.
Provided gestational surrogacy is legal, most societal guidelines recommend gestational carriers to have their own children, have had previous, uncomplicated deliveries to term, have delivered no more than five times (or three times by caesarian section), live in a stable environment, maintain a healthy lifestyle, have a reliable domestic support system, a clear-conscience about the process, and not do this under form of duress or against their better judgement.
In countries where compensating a gestational carrier is illegal, almost invariably any gestational carrier will be a close friend or family member of the intended parents.
At least within the United States, the vast majority of gestational carriers are under age 35 and societal guidelines call for them to be at least 21 years of age.
A major concern amongst all parties involved is that gestational carriers undergo the process for financial reasons. When investigators looked at data from six studies in the U.S. and U.K., they came to the conclusion the vast propenerance were motivated by altruism. Many gestational carriers tend to agree with that.
From a 2002 study published in the Journal of Assisted Reproduction and Genetics, we glean a an idea of who becomes a gestational carrier in countries where carriers can be compensated.
In the U.S., the majority tend to be married, have been a carrier before, ultimately continue contact with the child, and again, most start the process with a powerful desire to help others.
Generally speaking, few carriers believe their involvement plays a primary role in how the child turns out, though many believe they'll have an impact on the child’s long-term health.
Within this study, on a 5-point scale, most gestational carriers considered their compensation to be fair and would be willing to do it again. However, the process is not without its complexities and carriers saw real value in having both themselves and intending parents psychologically screened.