Here's some info on them from Media Matters:
ADF is classified as a 501(c)(3) public charity. According to the ADF website, the group is "a legal alliance defending the right to hear and speak the Truth through strategy, training, funding, and litigation." ADF defines this "Truth" according to a conservative Christian template, characterizing itself as "a servant organization that provides the resources that will keep the door open for the spread of the Gospel through the legal defense and advocacy of religious freedom, the sanctity of human life, and traditional family values."
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ADF focuses on three main issues:
"Guarding the Sanctity of Human Life": ADF is opposed to all forms of abortion and euthanasia.
"Protecting Family Values": ADF states that "God has defined marriage as one man married to one woman." ADF opposes same-sex marriage, adoption by same-sex couples, allowing gays and lesbians to serve in the military, and "
xpos children to explicit sex education materials contrary to parental approval.
"Defending Religious Freedom": ADF opposes efforts by "the ACLU and other radical activist groups ... to eliminate public expression of our nation's faith and heritage." Among other goals, ADF seeks to " historic and Christian acknowledgement in public places" and legalize prayer in public schools and at public school functions.
http://mediamatters.org/items/200510140005