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Below is ISTI's ever growing list of professionals who have dedicated themselves to maintaining and expanding their practices in the ongoing expansion of relational therapy. Please scroll down to review.

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Tammy Nelson

Tammy Nelson, PhD, LPC, CST, CSCT, is a sex and relationship expert, an international speaker, and author of several books including: “Getting the Sex You Want; Shed Your Inhibitions and Reach New Heights of Passion Together”; “The New Monogamy; Redefining Your Relationship After Infidelity”; "When You're The One Who Cheats"; and her forthcoming book "Open Monogamy", She is a Board Certified Sexologist, an AASECT Certified Sex Therapist, and a Certified Imago Relationship therapist, the Executive Director of the Integrative Sex Therapy Institute and the Director of M.A. & Ph.D. Human Sexuality and Sex Therapy Specialization, Daybreak University. She has been a featured expert in Glamour Magazine, Cosmopolitan, Redbook, MSNBC, Healthy Life Magazine, Shape, Men’s Health, Men’s Health UK, Woman’s Day, Women’s Health, Twist Magazine, New York Times, Washington Post and a source in Time Magazine. She writes for the Huffington Post and YourTango and gives workshops and Intensives for couples and trains therapists around the world on issues relating to sex and relationships.

Dr. Tammy



ISTI Certified Sex and Couples Therapist
Board Certified Sexologist
AASECT Certified Sex Therapist
Licensed Professional Counselor
Certified Imago Relationship Therapist
Licensed Alcohol and Drug Abuse Counselor
Practice in Los Angeles, California

Dianna Dresser-Heckman

Dianna Dresser-Heckman LCSW, CST, CSCT, is a Licensed Clinical Social Worker with a Master’s degree in Social Work from Virginia Commonwealth University and over 30 years of experience. Dianna’s professional experience includes working with all branches of the military. She spent over 6 years as a Military Family Life Consultant working at Quanitco Marine Corps Base. She worked with marines returning from Iraq and Afghanistan. She facilitated Post-Deployment PTSD groups as well as spouses’ groups.Dianna is an AASECT (American Association of Sexuality Educators, Counselors and Therapists) Certified Sex Therapist as well an ISTI Certified Sex and Couples Therapist. She has also trained in EMDR (Eye Movement and Desensitization and Reprocessing) and ART (Accelerated Reprocessing Therapy). Her passions are working with veterans’ suffering from symptoms of PTSD and marital reintegration post-combat. In 2018 Dianna was selected as a provider with the Headstrong Project where she works exclusively with veterans experiencing PTSD.




ISTI Certified Sex and Couples Therapist
6800 Backlick Road, Suite 202 Springfield, VA 22150

Pamela Finnerty

Pamela Finnerty, PhD, CST, CSCT has been a therapist in private practice specializing in relationship and couples therapy for over 30 years. Sexuality and aging have been areas of specialization since her earliest training in the 1970’s at the height of an explosive shift in paradigms of women’s sexual freedom. She ran women’s sexuality groups and taught human sexuality classes in the 1970’s and in the early 1980’s completed a certificate in gerontology as part of her doctorate. She went on to develop and teach one of the first courses in the country on Counseling Older Persons as part of her full-time academic career at George Washington University. Pamela is now an AASECT Certified Sex Therapist and an ISTI Certified Sex and Couples Therapist as well. In this later chapter of her long career, she is writing and teaching about the importance of sexual vibrancy and aliveness to the vitality and health of women and men as they age. The blossoming of her career-long priority to help older people free and become their best sexual selves is an important element of her own continuing power, strength, and joy.Individual, Couple, and Group Psychotherapy

Dr. Pamela



1700 17th Street NW Suite 601 Washington DC 20009

Lisa G Gordon

Lisa G Gordon is a Licensed Clinical Social Worker, AASECT Certified Sex Therapist, and ISTI Certified Sex and Couples Therapist. She has over 30 years of clinical experience in a variety of settings including group homes, hospitals, and outpatient clinics. After earning her Master’s in Social Work from Tulane University, Lisa enjoyed many years, working with adolescents, adults, and impaired professionals with drug and alcohol addiction. She served as director of the family program on the inpatient addiction unit of Ochsner Hospital in New Orleans, Louisiana. After returning to Virginia in the mid 90’s, Lisa served as Clinical Supervisor of Northern Virginia Family Service in Alexandria. She was also a consultant for local businesses and organizations, specializing in performance standards, performance improvement and team building, and facilitating groups and training on conflict management and the Myers-Briggs Type Indicator.For the past 20 years, Lisa has found her greatest clinical joy in her private practice. She works with individuals and couples experiencing challenges with life changes/transitions, depression, loss and grief, diminished passion, motivation or energy, communication problems, anxiety, decision making, and complexities of family dynamics. Lisa is passionate about helping her clients welcome and develop a positive and rewarding relationship with their unique, ever-changing sexual selves. Whether working individually or with a spouse or partner, Lisa uses her extensive training and integrates a variety of modalities to help clients experience their desired goals with issues of desire, arousal, pain, shame, negotiating differences, infidelities, fear, lack of accurate information, body/health challenges, orgasm, erectile and ejaculation functioning. She welcomes the opportunity to work with couples who have yet to enjoy sexual comfort and pleasure together, as well as couples who are “bored” or feel they have “lost” the delight, playfulness, erotic charge, or ability to enjoy sexual touch together.

Lisa G


AASECT Certified Sex Therapist
ISTI Certified Sex and Couples Therapist
6800 Backlick Rd. Suite 202, Springfield, VA 22150

Jennifer Greenberg

Jennifer Greenberg, LICSW, LCSW-C, CST, CSCT is an AASECT Certified Sex Therapist and ISTI Certified Sex and Couples Therapist (CSCT) in Bethesda, MD. Her specialties include working with individuals and couples around relationships and intimacy, including but not limited to navigating kink relationships and polyamory/Ethical Non-Monogamy; combat trauma and combat-related PTSD as it relates to relationships and intimacy; as well as being an LGBTQ+ ally and Health at Every Size (HAES) aligned. Jennifer is currently on the advisory board for ISTI. She is an AASECT Supervisor in Training and is accepting supervisees who are seeking AASECT Certification in Sex Therapy.




Psychotherapist, Couples Therapist
AASECT Certified Sex Therapist
ISTI Certified Sex and Couples Therapist
4405 East-West Highway, Suite 506, Bethesda, MD 20814

Gail Guttman

Gail Guttman, LCSW, CSCT, specializes in the integration of couples and sex therapy. Gail has been a Certified Imago Therapist since 1994 and an AASECT Certified Sex Therapist since 1984. Gail offers consultation and supervision groups. She has been twice recognized by Washingtonian magazine as a “Top Therapist” in sex and couples therapy. Gail is also an AASECT CE Provider, AASECT Certified SexTherapy Supervisor and an Imago Clinical Consultant. She is passionate about helping therapists to integrate couples and sex therapy and welcomes different theoretical orientations in order to help each therapist find their own path. Gail has presented on the subject of couples and sex therapy at the Integrative Sex Therapy Institute, Greater Washington Society for Clinical Social Workers, previous Imago therapy conferences, the University of Maryland and other professional organizations.




Guttman & Pearl Associates
Certified AASECT Sex Therapist and Sex Therapy Supervisor
Certified Imago Couples Therapist and Consultant
ISTI Certified Sex and Couples Therapist
6000 Executive Blvd., Suite 530, Rockville, MD 20852

Hani Miletski

Hani Miletski, Ph.D., MSW, CSCT, is a psychotherapist in private practice in Bethesda, Maryland, with over 25 years of clinical experience. She is a Certified Sex Therapist (Diplomate) and Supervisor by the American Association for Sexuality Educators, Counselors, and Therapists (AASECT). Dr. Miletski is a Licensed Clinical Social Worker with a Master’s degree in Social Work from the Catholic University of America, National School of Social Service, in Washington, DC, and with a Doctoral Degree in Human Sexuality from the Institute for Advanced Study of Human Sexuality, in San Francisco, California.She is the author of Mother-Son Incest: The Unthinkable Broken Taboo Persists, Understanding Bestialtiy and Zoophilia, and a variety of chapters and articles in professional journals. Dr. Miletski has been lecturing, training and supervising other therapists and professionals in the field of human sexuality throughout the world.




AASECT Certified Diplomate in Sex Therapy (Certified Sex Therapist)
AASECT Certified Supervisor
ISTI Certified Sex and Couples Therapist
6917 Arlington Road, Suite 300, Bethesda, Maryland 20814

Melvin Lee Phillips, Jr.

Melvin Lee Phillips, Jr., Ed.D., LCSW, CSAC, CST, CSCT is in private practice in Washington, DC where he treats chronic illness and sexual dysfunction. He is a Licensed Clinical Social Worker (LCSW) in Washington, DC, Maryland, and Virginia. He is also a Certified Substance Abuse Counselor (CSAC) in Virginia.He is an AASECT Certified Sex Therapist (CST) and an ISTI Certified Sex and Couples Therapist (CSCT). Dr. Phillips has been in private practice for more than a decade, working with couples on sexuality after chronic illness. He lectures on topics including sexuality, chronic pain, anxiety and stress management, caregiving stress, depression in the elderly, mindfulness and cognitive strategies for chronic pain, reclaiming sexuality for couples with chronic illness, ethical decision making, and the assessment of mental disorders. He has published in the Journal of Baccalaureate Social Work, conducting a research study on LGBTQ-Affirmative Teaching at Historically Black Colleges and Universities: Understanding Program Directors Views. He has been a featured expert in Teen Vogue and The Lily Newspaper. He writes for YourTango, Psych Central, and PsychAlive. He holds a Doctor of Education (Ed.D.) degree in Organizational Leadership with an emphasis in Behavioral Health from Grand Canyon University in Phoenix, AZ. In addition, Dr. Phillips is an adjunct professor in the Master of Social Work Program with the School of Social Work at Western New Mexico University.

Melvin Lee

Phillips, Jr.


Licensed Clinical Psychotherapist (DC, MD, VA)
Certified Substance Abuse Counselor (VA)
AASECT Certified Sex Therapist
ISTI Certified Sex and Couples Therapist
Host of the Sex & Chronic Illness Podcast
Facebook: @drleephillips
Instagram: @drleephillips
11160-C1 South Lakes Dr. Reston, VA 20190

Mary C. Ray

Mary C. Ray, LCSW, ACSW, SEP, addresses the physical, emotional, sexual, social, spiritual & intellectual components of a person/system. She provides individual, couple, family & group therapy as well as EMDR individual and group consultation & business consultation. Mary is an ISTI Certified Sex and Couples Therapist, an AASECT, American Association of Sexuality Educators Counselors and Therapist, Certified Sex Therapist, Certified in EMDR, an EMDR Consultant, an Imago Therapy Advanced Clinician, and a Somatic Experiencing Practitioner. She is also trained in other areas such as attachment, family systems, various models of couples therapy, and addiction treatment. Mary applies EMDR as a comprehensive relational psychotherapy to treat complex trauma and heal attachment wounds. Mary runs monthly consult groups. in person in Alexandria and on Zoom.

Mary C.



EMDR Certified and Consultant
ISTI Certified Sex and Couples Therapist
AASECT Certified Sex Therapist
Advanced Imago Clinician
CBT, GEX and PEX trained
Entrance: 201-C South Royal Street
Mailing: 201-B South Royal Street, Alexandria, VA 22314

Thomas Rea

Thomas Rea is a Licensed Clinical Social Worker and AASECT Certified Sex Therapist and ISTI Certified Sex and Couples Therapist in Bethesda, MD. He received his Master of Social Work degree from the University of Southern California and has over 10 years of experience providing individual and relationship psychotherapy to clients with various issues, including LGBTQI-related concerns, substance use disorders, problematic sexual behaviors and male sexual dysfunction. Before opening his private practice, Thomas worked in clinical case management.



ISTI Certified Sex and Couples Therapist
4405 East West Highway, Suite 411, Bethesda, MD 20814

Sue Walker

Sue Walker is a Licensed Clinical Social Worker, a Certified Imago Relationship Therapist, a Certified Prepare/Enrich Facilitator, an AASECT Certified Sex Therapist and an ISTI Certified Sex and Couples Therapist in Columbia MD. She received her Masters of Social Work degree from the University of Maryland Baltimore and has ten years of experience providing psychotherapy to couples and individuals. Her passion is assisting couples and individuals to meet their relationship and intimacy goals at every stage in their relationships.



ISTI Certified Sex and Couples Therapist
AASECT Certified Sex Therapist
Certified Imago Relationship Therapist
Certified Prepare/Enrich Facilitator
10632 Little Patuxent Pkwy Suite 340 Columbia, MD 21044

Nadia Williams

Nadia Williams is a Certified Sex Therapist through the American Association of Sexuality Educators, Counselors, and Therapists (AASECT) and a Certified Sex and Couples Therapist through the Integrative Sex Therapy Institute (ISTI). Her practice is located in the Canton neighborhood in Baltimore City where she sees a diverse population seeking help around a wide variety of sexuality issues. Nadia works with both individual clients and couples. She utilizes a variety of integrative therapeutic techniques ranging from cognitive-behavioral, mindfulness, dialectical behavior therapy, solution-focused, and acceptance and commitment therapy to assist clients facing difficulties around their sexual lives. Some of the issues/concerns she addresses include Partner Relational Problems, Sexual Abuse/Assault, Sexual Dysfunctions including Erectile Disorder, Female Orgasmic Disorder, Sexual Interest/Arousal Disorder, Substance Induced Sexual Dysfunction, Gender Dysphoria, Out of Control Sexual Behaviors (OCSB), Kink and Polyamory Relationships, Paraphilias and Fetishes, and other sexual dysfunctions related to STI’s. One of the most important topics in sex therapy that Nadia enjoys exploring with clients is how to have fun. In giving clients permission to have fun and be playful with sex and get more curious about their sexual selves, they feel more confident in themselves and more alive in all of their relationships. Nadia hopes to continue spreading the message of sexual curiousness for her clients and help create a sex-positive future for them.



Certified Sex Therapist
ISTI Certified Sex and Couples Therapist
2801 Foster Avenue, Baltimore, MD 21224

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