1880, he thought that the ideal ages for husband and wife at marriage would be if the woman's age was half the husband's age plus 10. Self-made graphic, with layout partially influenced by the PD image en:image: Half Plus Seven Graph 2.
The rule is widely cited, but its origins are hard to pin down.
In its earlier incarnations, it seemed to be a prescription for an ideal age difference rather than the limit of what’s okay.
According to the rule, the age of the younger partner (regardless of gender) should be no less than seven more than half the older partner’s age.
Martin, then, shouldn’t date anyone younger than 26 and a half; Lawrence shouldn’t go above 34.
[[Woman is sitting on the ground with her elbows on her knees and her hands on her chin.