Comparison of Weekly Somatrogon to Daily Genotropin in Children Born Small for Gestational Age or With Idiopathic Short Stature.

1. Diagnosis of SGA or ISS. SGA, defined as born with a birth weight and/or length \<-2 SDS below the mean for gestational age. ISS, defined as height \< -2 SDS for age and gender without evidence of GHD
2. Females aged ≥3 years and \<9 years. Males aged ≥3 years and \<11 years
3. Pre-pubertal- Tanner stage 1 for breasts and testes.
4. A bone age of not more than chronological age recorded in previous 8 weeks.
5. Current height \< -2 SDS for age and gender.
6. Participants using hormonal replacement therapy(s) must be on an optimized and stable treatment regimen (hormone levels within normal ranges on screening) for at least three months prior to screening
7. Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, and other study procedures.

Exclusion Criteria:

1. History of cancer, radiation therapy or chemotherapy.
2. History of GHD.
3. Children who are small due to malnutrition, defined as a Z score of weight for height and/or BMI below -2 for age, according to national standards.
4. History of HIV-positive, acquired immune deficiency syndrome (AIDS), hepatitis B, hepatitis C, or tuberculosis.
5. Microcephaly (Head Circumference \< -2 SDS)
6. Any chronic disease or diagnosis, likely to affect growth, including but not limited to gastrointestinal disorder, celiac disease, untreated thyroid disease, diabetes mellitus and metabolic disorders.
7. Known or suspected skeletal dysplasias
8. Known or suspected chromosomal abnormalities
9. IGF-1 >2 SDS
10. Any disorder or condition which, in the opinion of the investigator, might jeopardize participant's safety or compliance with the protocol
11. Prior exposure to growth promoting therapy
12. Current use of any prohibited concomitant medication(s): Any rhGH or growth-promoting therapy, Any therapy that affects appetite or weight, Psychiatric medications associated with weight changes and/or diabetes, excluding medications used to treat ADHD, Any androgen or estrogen therapy including over the counter supplements, Systemic corticosteroids (inhaled or oral) exceeding the doses: Inhaled: > 400 μg/day of inhaled budesonide or equivalent. Oral: > 8 mg/m2/day of oral hydrocortisone or equivalent.
13. Previous administration with an investigational drug within 90 days.
14. Fasting blood glucose >126 mg/dL
15. Renal impairment
16. Hepatic dysfunction.
17. Pregnancy
18. Known hypersensitivity to the components of the study intervention