Other factors tied to increased autism risk, though to a lesser degree, included congenital malformations, breech and other kinds of abnormal birth positions, multiple birth, a low 5-minute Apgar score, weighing less than 5.5 pounds at birth, umbilical cord complications, fetal distress, being small for gestational age.
SILVER vs CLAD: Some of the Eisenhower Dollars issued between 1971 and 1976 were composed of 40% Silver. These were Special Issues available only from the U. S. Mint which sold them at a premium. Eisenhower Dollars issued for general circulation were Clad: composed of a mixture of nickel and copper. D (Denver): The 'D' mint mark is located on the obverse between the date and Eisenhower's neckline. S (San Francisco): The 'S' mint mark is located on the obverse between the date and Eisenhower's neckline. Note: Dollars struck in Philadelphia bear no mint mark.
I once saw an 1893-S Morgan Dollar at a coin show, and as the potential buyer inspected the coin, the S fell off the coin! Someone had cut the S off another, more common, Morgan Dollar and glued the shaved mint mark onto the back of an 1893-P.