teratogens

Recently a baby boy was born in India with two penises and four legs. How do '"parasitic twins" develop and what causes this? And what conditions prompt duplications in the female anatomy?
Smoking is bad. Bad for mom. Bad for the unborn and born baby alike. Now, a new study reinforces its adverse effect on the developing child, with a focus on the damage done to the kidneys. 
Maternal opioid use is growing nationally. A new study reflects this, its impact on babies and regional disparities. As a result, babies are suffering withdrawal at alarming rates. Our directives must address the symbiotic relationships that perpetuate the current and intergenerational struggles of families.