The state Department of Health filed charges against Dr. Sjardo Steneker in December, alleging the popular family practice physician had sexual relationships with current and former patients — considered “unprofessional conduct” under state law.

According to a statement of charges filed on Dec. 3, Steneker got romantically involved with four women in 2007 and 2008; three of them were patients or former patients, the state says; one of them, charging papers show, was the mother of two children who were patients of Steneker.

Steneker, a Dutch-born physician who has practiced on Vashon since 1995, filed a response to the state denying all of the charges and requesting a hearing to contest the allegations. A hearing has been scheduled for Aug. 2-5.

In a statement, Steneker said he was “saddened to learn about these new allegations from the Department of Health. We are disputing the allegations. I am hopeful that this matter can reach a satisfactory resolution for all concerned.”

State law prohibits sexual relations between patients or former patients and their physicians. According to Taylor Linke, a case manager for the state Department of Health, the state forbids such relationships “because there’s oftentimes an initial balance of power differential between a healthcare practitioner and a patient. … The potential for harm comes into play when there’s a question of whether or not there’s an abuse of trust.”

According to the charging papers, Steneker, who is not married, terminated the physician-patient relationship a few days before getting involved with one of the women; in another instance, the patient had found a new primary-care doctor one year before the relationship started.

State law, however, says doctors are not to get involved with former patients; the length of time that must pass before such a relationship can begin depends on a number of factors, according to state code, including the nature of the patient’s health problems, “the degree of emotional dependence and vulnerability” and the extent to which the patient has confided in the physician.

The state launched an investigation a year ago, after receiving an anonymous tip, Linke said. Sanctions, should Steneker be found guilty, range from a minimum of two years of state-mandated oversight to a five-year suspension of his medical license.

Steneker, who has a large practice on the Island, said in his statement that he remains “committed to providing the highest-quality medical treatment to each patient at Vashon Family Practice.”

His practice, he added, “provides significant patient services to the under-served patient population in this rural, Island community. I am privileged to receive very positive and longstanding support from my large clientele of Island residents.”

State health officials have charged Steneker with infractions twice before. As a result of the first set of charges, he was ordered to pay a fine and take an ethics course. The state dropped the second set of charges in March 2008, after a three-member panel said he had not committed the alleged infractions and deserved a “public exoneration.”