It can be, depending on the motive or method. Providing a full treatment of the topic goes beyond the scope of this forum. Christian Life Resources, an organization within WELS, has extensive information on the subject. This link will take you to that part of their website. You might want to begin by reading the three-part Birth Control Series.
WELS Center for Mission and Ministry
N16W23377 Stone Ridge Drive
Waukesha, WI 53188-1108
8:00 a.m.-4:30 p.m.