A person of genius should marry a person of character. Genius does not herd with genius.
 Oliver Wendell Holmes Sr., The Professor at the Breakfast-Table (1860). copy citation

Context

“It is the most momentous question a woman is ever called upon to decide, whether the faults of the man she loves are beyond remedy and will drag her down, or whether she is competent to be his earthly redeemer and lift him to her own level. A person of genius should marry a person of character. Genius does not herd with genius. The musk-deer and the civet-cat are never found in company. They don't care for strange scents,—they like plain animals better than perfumed ones. Nay, if you will have the kindness to notice, Nature has not gifted my lady musk-deer with the personal peculiarity by which her lord is so widely known.” source