Our search resulted in 94 potentially relevant articles, of which 30 articles are duplicates. From the 64 articles identified, a total of 43 articles were screened for eligibility; and 33 articles met the full inclusion criteria (Fig. 1).

They included 41 patients with aphallia. The results of these 33 studies are summarized in Table 1.

The most cases were reported in the USA which were 31% (n:13) of all cases [2, 7, 8, 12, 16, 30, 32,33,34], followed by India with 21% (n:9) [14, 18, 19, 21, 25, 29, 34] Iran with 12% (n:5) [5, 13, 17], China with 7.3% [1, 6, 23], Turkey with 4% (n:2) [15, 31], France with 4% (n:2) [23, 27], Japan with 4% (n:2) [26, 27], Morocco with 4% (n:2) [9, 10], Mexico with 2% (n:1) [3], UK with 2% (n:1) [11], and Senegal with 2% (n:1) [22].

The majority of cases involve males with 97% (n:40) of all cases (1–3,7–29), and 2% (n:1) was female [2]. Of the 35 cases, the majority with 48% (n:20) cases were term neonates [2, 3, 8,9,10,11,12, 14, 17, 18, 21, 22, 25, 28, 30, 33], while 19% (n:8) were preterm neonates [2, 13, 24, 26, 32, 34], 9% (n:4) were infants [1, 16, 25, 34], 9% (n:4) were under five [5, 7, 19, 27],and 12% (n:5) were over 5 years old [6, 15, 23, 29, 31]. The patient with the lowest gestational age was 31 weeks [13], with the oldest patient ‘s age was 31 years old [23].

Only 14 cases reported weight. As many as 19% (n:8) of cases reported low birth weight neonate [13, 18, 21, 25, 26, 32], and 14% (n:6) of cases were normal birth weight neonates [9, 11, 14, 17, 25, 27]. The case with the lowest birth weight was 1,440 g [26] and the case with the largest birth weight was 4,000 g [25]. All characteristic data are shown in Table 2.

On physical examination, as many as 95% (n:39) cases reported scrotum development, and 2% (n:1) case reported well-formed labia major [2]. From 39 cases, 85% (n:35) cases reported normal scrotum development [1,2,3, 5,6,7,8,9,10,11,12,13,14,15,16,17,18,19, 22,23,24,25, 27,28,29,30,31, 33, 34], and 9% (n:4) reported bifid scrotum [13, 21, 26, 32]. Almost all male cases reported testicular development (with 39 of the 40), with 82% (n:34) with descending testis [1,2,3, 5,6,7, 9,10,11,12,13,14,15,16,17,18,19,20,21,22,23, 25,26,27,28,29,30, 32,33,34] and 12% (n:5) with undescendent testes [8, 24, 25, 31].

The majority of the patients’ anus was in a normal position in 78% (n:32) cases [1,2,3, 5,6,7, 9,