Still waiting to hear the source of those statistics.
Regarding the source of stats.....I remember hearing this 10-12 years ago, when I had remarried my current husband, and had a young daughter from a disastrous first marriage.....and thinking, how awful this is for the good stepfathers, like my husband. I don't recall who did the studies.
If you do a google search though, you will see that social service agencies do consider it (biologically unrelated adult males in a household) in risk assessment of child abuse. Rightly or wrongly.
I agree with you that a stepparent can be a great blessing, as my husband has been for my daughter. He is now her Daddy, as he adopted her ten years ago this month.