Through research on the Genealogy of my Murray Line, my father's side, I have found that as far back as 1840-41, which is when complete census’ began, there have been 3 sets of boy/girl twins born.
The first that I found was in 1857 to my 2nd great grandfather, WILLIAM MURRAY AND MARY ANN BARWISE of Cumberland, England; the births being: James and Catherine Murray.
The second was in 1901 to my grandfather, GEORGE MURRAY AND MARY DAVIS of Pittsburgh, Pennsylvania; the births being, my father, Walter Malone and Mary Ann (Pauline) Murray.
The third was in 1956 to my sister, Betty Murray Hankins and Harold Walker Rinehart of Pittsburgh, Pennsylvania; the births being: Sharman Elaine and Gary Wayne Rinehart.
On my Mother's side,the Weir's, I found 1 set of boy twins born in 1885.