"Before his salvation in 1980, David struggled with a serious bondage to pornography and other sexually addictive behaviors. He is the author of Sexual Healing: A Biblical Guide to Finding Freedom from Sexual Sin and Brokenness." He isn't involved in ex-trans activity per se, but considers transgenderism in the same group as homosexuality, promiscuity, pornography, etc. Jerry Leach quotes Sexual Healing extensively and Foster interviewed Leach which he published. Read more at his bio.
On page 360, Foster repeats the reparative therapy belief that transgender identify "stems from a profound disassociation from one's own gender group. In one way or another they have gotten the message that they are unacceptable or incapable of operating as the gender that they were born." On page 361 he equates cross dressing with fetishism.