Hannah is 5 years old. she has been diagnosed with adhd and shows signs of learning disabilities. her doctor suggests that hannah's problems could be the result of prenatal exposure to though he stresses that the link is not straightforward at this time

Prenatal exposure to smoking can be potentially harmful to a unborn fetus and has been linked to ADHD and learning disabilities. Cigarettes contain nicotine and this is the harmful substance known to have adverse effects of the fetus because it the placenta causing neurological insults to the fetal brain. ADHD is also hereditary so this is why the doctor stresses that the link is not straightforward.

Ithink the dna sequences may vary but the amino acid sequences are identical.