According to his deductions, twins occur once in 88 births; triplets, once in 7910; and quadruplets, once in 371,126.

Recent statistics supplied by the Boards of Health of New York and Philadelphia place the frequency of twin births in these cities at 1 in every 120 births, while in Bohemia twins occur once in about 60 births, a proportion just twice as great.

Of 150,000 twin pregnancies studied by Veit, in one-third both children were boys; in slightly less than one-third both were girls; in the remaining third both sexes were represented.
Authentic records of 5 and 6 at a birth are extremely rare and infinitesimal in proportion.

The reputed births in excess of 6 must be looked on with suspicion, and, in fact, in the great majority of reports are apochryphal.
The examples of multiple births of a single pregnancy will be taken up under their respective numbers, several examples of each being given, together with the authorities.

Many twin and triplet brothers have figured prominently in history, and, in fact, they seem especially favored.