Inclusion Criteria:  All Parts (A1, A2, B)  Subject's parent(s)/legal representative(s) providing consent must be 18 years or older Biological mother and/or biological father and/or full sibling(s), have a history of asthma, atopic dermatitis, food allergy, or allergic rhinitis as determined by the screening questionnaire Subject's parent(s)/legal representative(s) (if appropriate according to local laws) is/are willing and able to give informed consent for participation in the study Subject's parent(s)/legal representative(s) (if appropriate according to local laws) is/are willing and able, in the PI's opinion, to comply with all study requirements  Part A1 Only  Inclusion criteria 1-4 for all parts plus:  5 (A1). Subject is between 1 year and < 6 years old at the time of enrollment  Part A2 Only  Inclusion criteria 1-4 for all parts plus:  5 (A2). Subject is between 28 days and < 12 months of life at the time of enrollment 6 (A2). Subject's parent(s)/legal representative(s) do not plan to give probiotics (including infant formula that contain probiotics) to the subject during the trial  Part B Only  Inclusion criteria 1-4 for all parts plus:  5 (B). Subject is ≤ 7 days of life at the time of enrollment. Sites should make every effort to enroll newborns as soon as possible after birth.  6 (B). Subject has a birthweight ≥ 2.5 kg and ≤ 4.5 kg 7 (B). Subject's parent(s)/legal representative(s) do not plan to give probiotics (including infant formula that contain probiotics) to the subject from the time of birth to the end of the trial.  Exclusion Criteria:  All Parts (A1, A2, B)  Subject's twin (or higher order multiple) is enrolled in STMC-103H-102 Subject has any congenital abnormalities or condition, significant disease, illness, physical exam finding, or disorder that, in the opinion of the PI, may put the subject at safety risk or is likely to hinder feeding or affect metabolism that may influence the results of the study. (Neonatal hyperbilirubinemia (jaundice), including jaundice that requires phototherapy, should not be considered exclusionary). Subject is acutely ill or on systemic antibiotics at the time of enrollment Subject is participating in another interventional clinical study involving investigational medication, formula, probiotic, or prebiotic use within 30 days (or five half-lives, whichever is longer) of this study Subject has evidence of immune deficiency/immune compromise in the judgment of the investigator  Part B Only  Exclusion Criteria 1-5 for all parts plus:  6 (B). Subject was born at < 35 weeks' gestation 7 (B). Biological maternal medical condition during the pregnancy that, in the opinion of the PI, may put the subject at risk because of participation in the study. (Maternal antibiotics during the time of delivery should not be considered exclusionary.)