Final answer:
It is false that there have been no known birth defects associated with the mother's use of marijuana during pregnancy; marijuana can cause problems with fetal and child development.
Step-by-step explanation:
The statement is false. Research and reports from health organizations indicate that the use of marijuana during pregnancy can be associated with negative outcomes, including problems with child development during and after pregnancy. Marijuana contains chemicals that may interfere with fetal development, potentially leading to complications such as low birth weight and developmental problems.
Marijuana's constituents, similar to those in tobacco smoke such as carbon monoxide and other substances, can reduce blood oxygen levels, which is detrimental to the developing fetus. The Centers for Disease Control and Prevention (CDC) and other health authorities recommend against the use of marijuana during pregnancy due to these risks. Substances like nicotine and alcohol, known teratogens, have demonstrated severe effects on fetal development, and while less is known about marijuana, the potential for harm exists.