[Jack]

"In a household with a homosexually-behaving adult, the foster child would be exposed to additional stress with the impact of the significantly higher rates of psychological disorder (particularly affective disorders such as depression), suicidal ideation, suicide attempt, suicide completion, conduct disorder, and substance abuse in homosexually-behaving adults. Thus, a foster placement in a household with a homosexually-behaving adult would risk exposing foster children to a substantially higher level of harm because research indicates that parental affective disorder results in higher rates of child depression, child maltreatment and neglect, as mediated by interpersonal stress processes."

The vast majority of foster children killed by their adoptive parents were placed with heterosexual couples.

Not only should homosexual adoption be ILLEGAL but children already under the care of homosexual partners should be relocated immediately.

Thus, using your "reasoning", children in the care of heterosexual couples should immediately be relocated for their own good and the practice of allowing heterosexuals to adopt children should be made illegal.
Studies like you quote have little interest in the welfare of children. It's underlying agenda is simply to stigmatize gay unions even further.