Children who are raised on strict vegan diets do not grow normally:
ncbi.nlm.nih.gov/pubmed/4067152
ncbi.nlm.nih.gov/pubmed/8005079
Children develop rickets after prolonged periods of strict vegetarian diets:
ncbi.nlm.nih.gov/pmc/articles/PMC1874810/pdf/canmedaj01383-0052.pdf
"There are some links between vegetarians and lower birthweight and earlier labour"
ncbi.nlm.nih.gov/pubmed/7788369
Effects of vitamin B12 and folate deficiency on brain development in children:
ncbi.nlm.nih.gov/pmc/articles/PMC3137939/
"Particular attention should be paid to adequate protein intake and sources of essential fatty acids, iron, zinc, calcium, and vitamins B12 and D. Supplementation may be required in cases of strict vegetarian diets with no intake of any animal products."
ncbi.nlm.nih.gov/pmc/articles/PMC2912628/
These next five are case studies:
Cerebral atrophy in a vitamin B12-deficient infant of a vegetarian mother:
ncbi.nlm.nih.gov/pubmed/25076673
Severe megaloblastic anemia in child breast fed by a vegetarian mother:
ncbi.nlm.nih.gov/pubmed/8442642
Consequences of exclusive breast-feeding in vegan mother newborn - case report:
ncbi.nlm.nih.gov/pubmed/19748244
Nutritional vitamin B12 deficiency in a breast-fed infant of a vegan-diet mother:
ncbi.nlm.nih.gov/pubmed/3948463
"We report the case of a 7 month-old girl that presented with acute anemia, generalized muscular hypotonia and failure to thrive. Laboratory evaluation revealed cobalamin deficiency, due to a vegan diet of the mother."
ncbi.nlm.nih.gov/pubmed/18293883