Martha and Susan are planning to have a child. Martha will be the biological mother. Some of the research on how fathers impact prenatal development applies to Susan as well. Which of these are relevant for Susan and Martha's child?

a. Susan should work more even if it causes stress in the relationship to be sure the family is economically sound.
b. Susan should not smoke because second hand smoke is bad for mother and baby.
c. Susan should refrain from alcohol or drug use because it may lead to chromosomal damage transmitted via sperm.
d. Susan should be sure to exercise regularly as this is ideal for the baby's health.

b