Positive displacement using a connector with dual diaphragms is provided. For example, the connector includes a single fluid flow path, an air chamber and a valve. The single fluid flow path is configured for delivering fluid to a person and configured for receiving fluid from a person. The air chamber configured for expelling air from the air chamber when an actuator is inserted into the connector and for receiving air into the chamber when the actuator is removed from the connector. The valve plug comprises two diaphragms that separate the air chamber from the single fluid flow path. The valve plug is configured for creating positive displacement by returning the valve plug to its uncompressed state when the actuator is removed from the connector.