Meet the Clydesdale. The Clydesdale breed once almost faced extinction. Even though there is little practical use for heavy horses today because their muscle power has been replaced by machinery, breeders and enthusiasts have ensured that the breed is increasing, rather diminishing in numbers.
1 Over the three decades, the twin birth rate rose by 76 percent, from 18.9 to 33.2 per 1,000 births (or from 1.9 percent to 3.3 percent of all births) (Figure 1). 2  Increases in the twin birth rate averaged more than 2 percent a year from 1980 through 2004 (peaking at more than 4 percent from 1995 to 1998).
With twins, a common question parents have is whether the twins are identical or fraternal. DNA Diagnostics Center offers a twin zygosity DNA test that definitively determines whether twins are identical or fraternal. A twin zygosity DNA test is a simple procedure performed sometime after the babies are born. Some parents choose to start testing right away, while others prefer to wait to initiate testing until the twinsâ features emerge later in life.