"Countries that are under the control of Sunni populations do not permit surrogacy. In Iran, where Shia are the majority, Ayatollah Khomeini allowed surrogacy in Islam, but with one condition: the resulting child must be recognized as the child of the donor father.This works well if an infertile couple contributes the egg and sperm, and then has it grown inside a third party surrogate mother, but it would not work well if the wife of the infertile couple wishes to carry the child using the sperm of a third party donor. Many Shia in some other countries actually agree with the Sunni point of view, but Iran’s position has made other countries consider their objection.The majority of the Shia scholars are willing to legitimise the issue. Ayatollah Musavi Bojnordi refers to the principle of (اصالة الحل) in Islamic jurisprudence. Everything is Halal unless it has been proved otherwise. Surrogacy is common in Iran. Act of donating Gamete or embryo donation was passed by parliament on 19 July 2003 and it has been approved by Guardian Council (شوراي نگهبان) on 29 July 2009. Article no 1) All of the fertility centres would be allowed to practice artificial insemination. Article no 2) Demand for donating embryos should be from both sides of legal couples. 

References:

Musavi Bojnurdi, Seyed Mohammad. Hoghoghe Khanevadeh
Safaei, Seyed Hosain & Imami, Asadolah. Mokhtasar Hoghoghe Khanevadeh
www.islamquest.net
http://www.mums.ac.ir/midwifery/fa/wom_heal_help_rent# (University of Mashhad) 
http://www.surrogacyclinics.com/surrogacy-and-islam/

(From a presentation by Fatemeh Ghiabi)