"Hypophyso-Gonadal Function in Humans during the First Year of Life," from The Journal of Clinical Investigation, March 1974; first section is "Evidence for Testicular Activity in Early Infancy." When the paper was written it was not yet known if the high T male newborns experience is generated from the testicles; it since has been proven to that the testes produce the T surge. The paper concludes:

"Plasma testosterone increase in male infants in the first months of life probably reflects testicular activity and might have an important physiologic role... The present data indicate that the testes are active in the postnatal period... It is possible that the surge of testosterone in the first 3 months of life plays a role in the future life pattern of the male human being."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC333063/

"Dihydrotestosterone and Its Relationship to Testosterone in Infancy and Childhood," published in the Journal of Clinical Endocrinology and Metabolism in May 1979:

"A cross-sectional and longitudinal study of the change in dihydrotestosterone (DHT) and testosterone (T) serum concentration was undertaken in infants from birth to 18 months to elucidate the differences in the concentration of DHT and T in male and female infants. In addition, changes in DHT, T, and the T:DHT ratio were studied in males from infancy to adulthood. Both DHT and T in cord blood were significantly higher in male than in female infants (P < 0.005 and P = 0.01, respectively). Postnatally, in male infants, there was a parallel rise in DHT and T to pubertal levels, resulting in a constant T: DHT ratio (mean ± SD, 4.9 ± 2.7). After hCG stimulation, the T: DHT ratio was similar in this age group (mean ± SD, 5.3 ± 1.7). Both DHT and T decreased sharply at age 6 months in young male infants..."

"Activation of the Hypothalamic-Pituitary-Gonadal Axis in Infancy: Minipuberty" published in Hormone Research in Pediatrics, August 2014:

"The postnatal gonadotrophin surge results in gonadal activation in both sexes. In boys, testosterone levels rise to a peak at 1-3 months of age and then decline following LH levels. Postnatal HPG axis activation is associated with penile and testicular growth and therefore considered important for the development of male genitalia... Testosterone levels in boys are low in the cord blood but start to increase after 1 week of age, peak to pubertal levels at 1-3 months and then decline to low prepubertal levels by approximately 6 months of age.

"In girls, elevated gonadotrophin levels result in the maturation of ovarian follicles and in an increase in oestradiol levels.

"Biological significance and possible long-term consequences of this minipuberty remain elusive, as do the mechanisms that silence the HPG axis until puberty..."

"Sex Differences in Reproductive Hormones During Mini-Puberty in Infants With Normal and Disordered Sex Development" published in the Journal of Clinical Endocrinology and Metabolism" in August 2018:

"A transient postnatal activation of the hypothalamic-pituitary-gonadal axis, also termed mini-puberty, occurs in healthy infants. This rise in gonadotropins, which peaks when the infant is between 1 week and 3 months of age, appears to show a marked sexual dimorphism with preponderance of LH in boys and of FSH in girls. A subsequent rise in serum concentrations of the gonadal hormones is also seen in bothsexes, with preponderance of testosterone (T), inhibin B, and anti-Müllerian hormone (AMH) in boys and estradiol in girls. Concentrations of LH, FSH, and T in boys and of LH and T in girls decrease to prepubertal levels in the following months, whereas the elevation of FSH and estradiol is more prolonged in girls."

https://academic.oup.com/jcem/article/103/8/3028/5037960

Mayo Clinic Lab Values for TESTOSTERONE, TOTAL say that the normal ranges for Males by age from infancy to young adulthood are: 0-5 months: 75-400 ng/dL - 6 months-9 years: <7-20 ng/dL - 10-11 years: <7-130 ng/dL - 14 years: <7-1,200 ng/dL 15-16 years: 100-1,200 ng/dL - 17-18 years: 300-1,200 ng/dL - 19 years or above: 240-950 ng/dL

Mayo Clinic says normal Male T levels before and during puberty are as follows: Tanner Stage I (prepubertal): <7-2/ Tanner Stage II: 8-66/ Tanner Stage III: 26-800 /Tanner IV: 85-1,200 Tanner Stage V (young adult): 300-950

https://www.mayocliniclabs.com/test-catalog/Clinical+and+Interpretive/83686

Lots of other papers out there if you search such terms as "mini puberty in infants" and "neonatal testosterone surge"

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4462291/

https://pediatrics.aappublications.org/content/pediatrics/early/2016/06/07/peds.2016-1301.full.pdf

https://www.researchgate.net/publication/283588320_The_Postnatal_Endocrine_Surge_and_Its_Effects_on_Subsequent_Sexual_Growth

https://pediatrics.aappublications.org/content/138/1/e20153561