It is believed that pregnancy and motherhood ipso facto interfere with military duties...Granting of maternity leave would result in having ineffectives; replacements could not be procured while the woman remained on the active list; and the mother of a small child would not be readily available for reassignment. Necessary rotation of duty assignments would require the family unit to be broken up for considerable periods of time, or at least until the husband made the necessary provisions to establish the home at the mother's new duty station...It is believed that a woman who is pregnant or a mother should not be a member of the armed forces and should devote herself to the responsibilities which she had assumed, remaining with her husband and child as a family unit.

This sort of reasoning, typical of the times, formed the basis for Marine Corps regulations on the subject until 1970. The rules were very strictly enforced and any responsibility for children forced the separation of a woman Marine from the service.