Ngesikhathi sokuzalwa, iningi lezingane linamehlo aluhlaza okwesibhakabhaka. Kepha lo mbala awuyona eyokugcina. Kuzothatha izinyanga ezimbalwa ukwazi ngokuqinisekile ukuthi ekugcineni bazoba namehlo kababa wabo, umama wabo, noma omunye wogogo nomkhulu wabo.

Izinto ezibonakalayo zombungu ziqala ukwakheka kusukela osukwini lwama-22 ngemuva kokukhulelwa. Phakathi nenyanga yesi-2 ekhulelwe, kuvela izinkophe zakhe, ezizohlala zivaliwe kuze kube yinyanga yesi-7 ekhulelwe. Izinhlamvu zamehlo akhe bese ziqala ukuhamba kancane kakhulu futhi zibonakala zizwela kuphela umahluko ekukhanyeni.

Ngoba ayisetshenziswa kangako, ukubona kungumqondo omncane othuthukisiwe embungwini: uhlelo lwayo olubukwayo olokugcina ukubekwa endaweni, ngemuva kohlelo lokuzwa, olfactory noma oluthambile. Kunoma ikuphi, amehlo engane akulungele ukusuka ekuzalweni. Noma kuzobathatha izinyanga ezimbalwa ngaphambi kokubona njengomuntu omdala.

Ngesikhathi sokuzalwa, izingane eziningi zinamehlo aluhlaza okwesibhakabhaka ngoba izingulube ezinemibala ebusweni be-iris yazo azikenziwa zisebenze. Ngakho-ke ungqimba olujulile lwe-iris yabo, grey ngokwemvelo eluhlaza okwesibhakabhaka, olubonakala obala. Ngakolunye uhlangothi, izingane ezinemvelaphi yase-Afrika neyase-Asia, zinamehlo ansundu ngokusa.

Emasontweni ambalwa okuqala, amangqamuzana e-pigment akhona ebusweni be-iris kancane kancane aziveza wona futhi awufake umbala, aze awunikeze umbala wawo wokugcina. Kuncike ekugxileni kwe-melanin, okufanayo nokunquma umbala wesikhumba nezinwele zakhe, amehlo engane ayoba luhlaza okwesibhakabhaka noma nsundu, ukukhanya okuncane noma okuncane noma okumnyama. Amehlo ampunga naluhlaza, angajwayelekile kakhulu, abhekwa njengemithunzi yale mibala emibili.

Ukuhlungwa kwe-melanin, ngakho-ke umbala we-iris, kunqunywa ngokofuzo. Lapho abazali ababili benamehlo ansundu noma aluhlaza, ingane yabo inethuba elicishe libe ngama-75% lokuba namehlo ansundu noma aluhlaza futhi. Ngakolunye uhlangothi, uma bobabili benamehlo aluhlaza okwesibhakabhaka, bangaqiniseka ukuthi ingane yabo izogcina amehlo aluhlaza abazalwa benayo impilo yabo yonke. Kufanele wazi futhi ukuthi umbala onsundu kuthiwa "ubusa". Ingane enomzali oyedwa enamehlo ansundu kanti enye enamehlo aluhlaza kaningi izodla ifa lomthunzi omnyama. Ekugcineni, abazali ababili abanamehlo ansundu bangaba nengane enamehlo aluhlaza okwesibhakabhaka, inqobo nje uma omunye kogogo nomkhulu wakhe uqobo enamehlo aluhlaza okwesibhakabhaka.

Imvamisa kuthatha izinyanga ezi-6 kuya kwezi-8 ukwazi umbala wokugcina wamehlo wengane.

Kwenzeka ukuthi umuntu ofanayo unamehlo anemibala emibili. Lo mkhuba, owaziwa ngaphansi kwegama "lamehlo odonga", uphethe igama lesayensi le-heterochromia. Lapho le heterochromia ikhona kusukela ekuzalweni, ayinamthelela empilweni noma ekubukekeni okubonakalayo kwalowo oyigqokile. Uma kwenzeka kulandela ukuhlukumezeka, noma ngaphandle kwesizathu esisobala, kudinga ukubonisana nodokotela ngoba kungaba uphawu lokulimala.