My greatest credentials are my results and the results of my clients in this area. Like you, I'm sure, I know many men and women with MDiv's, Masters, and PhDs in areas related to this who nevertheless have extremely dysfunctional marriages and intimate lives, and are often spreading little more than how to recreate that dysfunction, regardless of what their schooling might be. There are plenty of people with lots of letters behind their name who I would never send anyone to.
But in a nutshell, here are the pieces of my education and experience that pertain to this teaching:
Johns Hopkins undergraduate degree in medical writing (Writing Seminars, concentration medical and scientific writing), Phi Beta Kappa (hence the course being heavy on medical studies and diagrams about this from the scientific side!)
Trinity School for Ministry in Ambridge, PA, to study "Sex, Gender, and the Gospel" (hence it being heavy on the theology side too :) )
Georgetown University Masters, Communication, Culture, Technology, (where I learned how to facilitate transformation for people through online portals.)
American Association of Christian Counselors, Life Coach
Symbis Certified Marriage and Pre-Marriage Coaching Facilitator
Level 1 training through the Christian Healing Ministries program
Love and Fidelity board member at Georgetown University (Love Saxa) - group supporting and teaching on traditional marriage
On the Marriage Ministry board with my husband at the Falls Church Anglican for 2 years. As the 'young, relevant voice' :)
3 years in ministry leading young women and young married couples on staff at a 4000 member church that was going through a split over the Biblical doctrine on sexuality. (The Falls Church Anglican)