A connector assembly comprising: a first connector comprising: a first housing defining a first aperture, a lumen defining a fluid passage therethrough, and a first sealing surface disposed at an end of the lumen; a seal disposed around the first sealing surface; and a first valve (150, 1700) disposed over the first aperture; and a second connector comprising: a stem defining a fluid passage therethrough and defining a second sealing surface at a terminal end of the stem; a second housing surrounding the stem and defining a second aperture, wherein the second housing is configured to engage the first housing of the first connector; and a second valve disposed over the second aperture, wherein the second valve is configured to align with the first valve (150, 1700) when the second housing engages the first housing; wherein the stem is configured to move in relation to the first and second housings (100, 200) and through the first and second valves (150, 250), such that the first and second sealing surfaces matingly engage, characterized in that the first sealing surface faces radially outwardly from the lumen and forms a separate surface from an inner surface of a seal structure and fluid conduit, wherein the second sealing surface faces radially inwardly and forms a separate surface from an inner surface of the stem and an outer surface of the stem, and wherein the stem does not extend into a lumen defined by the inner surface of the housing, the stem engaging an outer seal surface of the seal structure. a first connector comprising: a first housing defining a first aperture, a lumen defining a fluid passage therethrough, and a first sealing surface disposed at an end of the lumen; a seal disposed around the first sealing surface; and a first valve (150, 1700) disposed over the first aperture; and a first housing defining a first aperture, a lumen defining a fluid passage therethrough, and a first sealing surface disposed at an end of the lumen; a seal disposed around the first sealing surface; and a first valve (150, 1700) disposed over the first aperture; and a second connector comprising: a stem defining a fluid passage therethrough and defining a second sealing surface at a terminal end of the stem; a second housing surrounding the stem and defining a second aperture, wherein the second housing is configured to engage the first housing of the first connector; and a second valve disposed over the second aperture, wherein the second valve is configured to align with the first valve (150, 1700) when the second housing engages the first housing; a stem defining a fluid passage therethrough and defining a second sealing surface at a terminal end of the stem; a second housing surrounding the stem and defining a second aperture, wherein the second housing is configured to engage the first housing of the first connector; and a second valve disposed over the second aperture, wherein the second valve is configured to align with the first valve (150, 1700) when the second housing engages the first housing; wherein the stem is configured to move in relation to the first and second housings (100, 200) and through the first and second valves (150, 250), such that the first and second sealing surfaces matingly engage, characterized in that the first sealing surface faces radially outwardly from the lumen and forms a separate surface from an inner surface of a seal structure and fluid conduit, wherein the second sealing surface faces radially inwardly and forms a separate surface from an inner surface of the stem and an outer surface of the stem, and wherein the stem does not extend into a lumen defined by the inner surface of the housing, the stem engaging an outer seal surface of the seal structure.