If i have some of the physical signs of down syndrome like a simian crease but don't have down syndrome, am i more likely to have a child with downs?

No: Some of the features seen in Down syndrome persons are also seen in other hereditary disorders, and some features are seen in normal people. A normal person can have a single horizontal palmar crease (simian crease), but his simian crease is just a trait he has, and has nothing to do with down syndrome. A normal person with a simian crease is not more likely to have a Down syndrome baby.

No: Down syndrome is usually almost 90% can be diagnosed prenatally. Visit your obstetrician as soon as you became pregnant and follow with all tests and imaging as prescribed.

No: Down syndrome is hereditary in approximately 1% of all instances. In the other 99% of cases Down syndrome is completely random and the only known factor that increases the risk is the age of the mother (over 35).