Gay adoption laws differ from state to state. It's completely banned in Florida and is completely open to gays in California.
There are three basic levels of gay adoption laws that the Human Rights Campaign has sectioned off to make understanding states' gay adoption laws easier to comprehend. Some states may, for example, have explicit laws addressing whether single gay, lesbian, bisexual and transsexual (GLBT) adopters can petition for adoption. Next, laws may or may not explicitly address whether a same-sex couple can jointly petition for adoption. And the third possible gay adoption scenario is one that allows a co-parent of the same-sex to adopt a partner's child.
For the most part, state laws are vague enough to be interpreted in favor of gay or lesbian adoption on a case by case basis. Gay adopters should consult an attorney before pursuing any kind of adoption, though. Certain countries abroad will not place an adoptee with someone who may be gay.
The animosity toward gay child adoption is founded in moral standings and personal preference. If a private agency, birth mother or private agency's case worker believes in a more traditional family dynamic, they reserve the right to not place the child. It's important to note that there is no empirical data indicating that gay or lesbian parenting is any less supportive or loving than heterosexual adoptive parents.