Lesbian breastfeeding

I am watching this interesting documentary on Netflix called "Breastmilk". It's all about breastfeeding, the good the bad and the ugly. It follows around several couples and their newborn babies on the journey with breastfeeding. One of the couples is a lesbian couple, from what I understand the baby was adopted, however both adoptive moms were able to breastfeed the baby. They said that having a baby will make you begin to lactate, but so will regular stimulation. 
Basically they had the baby latch on to their breasts for a couple of minutes every day and after just a few days they both began to lactate.
This is incredible to me! Have you ever heard about something like this? If this is true then why don't more parents who adopt choose to (try to) breastfeed?