There is plenty of evidence that adoption and home environments can make a lasting difference in children's school readiness, vocabulary, coping skills, and even IQ (Duyme, Dumaret, & Tomkiewicz, 1999;Hart & Risley, 1995; Maccoby, 2002) but no research that indicates it matters the gender of the parents who provide such an enriched environment. If you are truly interested in the long-term well-being of children, then concentrate your guidelines on what matters for them in the long run.
Duyme, Dumaret, & Tomkiewicz (1999). Procedings of the National Academy of Sciences of the United States of America, vol. 96.
Hart & Risley (1995). Meaningful differences in the everyday experiences of young American children.
Maccoby (2002). In Parenting and the child's world: Influences on academic, intellectual, and social-emotional development.