I had a really horrible experience with Big Bros. here in Tulsa.
I had references from my former pastor, elders in my church, etc.....no other strikes against me other than being openly gay.
I went thro' the fairly intrusive evaluation process only to be told that I would not be considered to be a big bro. because I had "unresolved issues with my ex...."
To begin with, who doesn't? We were civil however. The answer had a suspicious smell to it.
I challenged the executive director whom I knew slightly and finally he admitted that it wasn't me but rather that the local organization didn't want the possibility of bad press of having a gay big bro. There had been an incident of abuse some years prior.....and since then, just recently, a guy's been accused of abusing a kid he was big bro to.
Since that time, the national organization has officially added sexual orientation to its non-discrim. policy. And if you live in a state where discrimination is illegal, it may be less of an issue.
For me, it was a brutalizing and humiliating experience which has made me very wary of volunteering or supporting the organization. I went in, maybe kind of naive, but really hoping it could be an opportunity for me to help a kid in need and express my fathering/parenting instincts. While I have a number of nieces and nephews, they're all elsewhere in the US.
I hope it's different now. It could be a really great thing.